The Elder Scrolls V: Skyrim Special Edition

JOINING
To join the Thieves Guild, travel to Riften and come into contact with Brynjolf, who can be found at the market stalls during the day, or the Bee and Barb tavern during the night. Brynjolf will approach you and question your wealth before inviting you to help him with a little plot. This begins the first quest, A Chance Arrangement, in which you must steal a ring and plant it on another person.

After joining there are a few requirements before you can unlock this Achievement. These include completing the Main Quest, Tonilias Two Misc Quests and all 4 Special Jobs.


MAIN QUESTS
The first requirement is completing the main Quest line:

A Chance Arrangement

Taking Care of Business



Loud and Clear

Dampened Spirits

Scoundrel's Folly

Speaking With Silence

Hard Answers

The Pursuit

Trinity Restored

Blindsighted

Darkness Returns




MISCELLANEOUS QUEST
Tonilia will also occasionally have some Miscellaneous quests. You should complete these to avoid any issues, specifically after completing Scoundrel's Folly, as you will be offered the Miscellaneous quest: Speak to Tonilia about exchanging a piece of armor.

If you do not complete this quest, she will not talk to you about any other quests, including giving you Guild Master Armor and blocking you from progressing later.

You must keep at least one piece of Guild Armor to upgrade it, if you already got rid of all your Armor, you can find pieces near the beds in The Ragged Flagon - Cistern area, or more specifically in the North East Training Area, also in the Cistern.


SPECIAL JOBS
The other requirement is completing all 4 Special Jobs (otherwise known as City Influence Quests).

After joining the Guild, Delvin and Vex will offer you unlimited radiant quests, known as "Jobs".

You must complete five jobs in one region (Whiterun, Windhelm, Makarth or Solitude) to unlock that regions Special Job (Note: Riften is not required). In total you would be completing 20 of these jobs across the 4 regions.

The easiest jobs to complete in my opinion are Numbers and Shill. For efficiency you can receive a job from Delvin and Vex at the same time, completing them both before returning to minimise travel. Delvin and Vex can give you details about the other kinds of jobs if you wish to learn more.

If you receive a quest for a region you don't require (such as Riften or for an area you have already done 5 jobs and the Special Job) you can simply just talk to the quest giver again and choose to quit the job, and then receive a new one.

After completing 5 jobs in the same region, Delvin will talk to you about a "Special Job". The 4 required Special Jobs are for the Major Holds of Skyrim:

Imitation Amnesty in Whiterun

Summerset Shadows in Windhelm

Silver Lining in Markarth

The Dainty Sload in Solitude


MISCELLANEOUS QUEST
The other Miscellaneous quest from Tonilia should also be completed Deliver Moon Sugar to Ri'saad, which is given after completing three special jobs for the Guild.


ADDITIONAL INFO
You can complete these in any order you wish, I finished all 4 Special Jobs before completing the Main Quest. I also upgraded my armor after completing the Main Quest.


BECOMING GUILD MASTER
After all these requirements are done, speak to Brynjolf and a new quest should start called Under New Management. Complete the ceremony, then talk to Brynjolf again. He will tell you to retrieve your Guild Leader Armor from Tonilia (Note: For this step you do not require to already have a piece of Guild Armor).

Upon receiving your Master Guild Armor the achievement should pop!


QUICK CHECKLIST
A quick overview of what is required to begin the Under New Management Quest.

Main Quests
A Chance Arrangement
Taking Care of Business
Loud and Clear
Dampened Spirits
Scoundrel's Folly
Speaking With Silence
Hard Answers
The Pursuit
Trinity Restored
Blindsighted
Darkness Returns

Small Jobs
5 in Whiterun
5 in Windhelm
5 in Markarth
5 in Solitude

4 Special Jobs
Imitation Amnesty - Whiterun
Summerset Shadows - Windhelm
Silver Lining - Markarth
The Dainty Sload - Solitude

Two Misc Quests
Speak to Tonilia about exchanging a piece of armor
Deliver Moon Sugar to Ri'saad

Before we start I want to point out this should be done after completing the main story line of the thieves guild.

You need to do quests for both Delvin and Vex. What you want to do is do bedlam and sweep make sure that both the quests are in a town that you haven't done a special quest that gains influence for the thieves guild. This is simple with the shadowcloak ability. Make sure that you have the sweep quest marked to follow and not the bedlam one. To make sure they are in the same town just keep quitting the quest until they are in the same town. Go break into the the house and start stealing the items you need to steal. By stealing two of the items you will finish the bedlam quest go and steal the third to finish the sweep quest. Go return the quests and you will then be asked to start a special quest.

Go complete the special quest then rinse repeat. The four towns you need to gain influence are Riften, Markath, Whiterun, and Solitude. Also remember if you have done a special quest in that town don't go and do any side quests for that town its kind of a waste of time.

Edit: Its not Riften because you get that quest from Maven early on in the thieves guild its Windhelm. So Sorry for the confusion. :)

Credit to: IceWolfOfAlaska

Pressing ~ will open the console command window. (top left under ESC)

You want to type into the console:

setstage TGLeadership 200

Your achievement should pop.

Edit: Apparently you need to go to Riften and talk to Shadr first or it won't pop. I have no idea why this matters but several people confirm that it is needed.

I did this legit all the way through, not sure if you can CC some of the quests to make it faster or if they need to all be done legit but this is the order you need to complete them.

You need to complete all of the Thieves Guild main quests except for the last one (as far as I've seen), which includes all of the below:

A Chance Arrangement
Taking Care of Business
Loud and Clear
Dampened Spirits
Scoundrel's Folly
Speaking With Silence
Hard Answers
The Pursuit
Trinity Restored
Blindsighted
Darkness Returns

After Darkness Returns is complete, you become Guild Master but it's still work to get the Guild back to the former glory so Brynjolf says to do jobs for Delvin and Vex in the mean time. At this point, you have to do 5 jobs in 4 different holds on the map:

Whiterun
Markarth
Windhelm
Solitude

I think that CC'ing these quests is difficult because there's only 3-4 quest type per person you can do and if you repeat a quest type, the name is the same. Also, the location for each quest is random so if you complete all the quests needed for a hold but still get quests for that hold, just quit the quest and ask for another. They will tell you they won't give you any more quests if you keep quitting them, but they're bluffing. They also give you quests for Riften but they do not count at all towards the progress for the achievement so toss these back immediately.

After the 5th job in a hold, a special job is unlocked. After you complete all 4 hold's special jobs, you automatically start the final quest needed for the achievement, Under New Management. Completing the official Guild Master ceremony with you Guild Master armor (don't get rid of it before this) in Under New Management pops the achievement.

You might be able to play around with the CC's and make it faster, but I didn't bother and just played legit. Using CC's at different times caused more glitchy issues for me so I gave up using them. Hope this helps anyone who is stuck on this achievement!

Credit to D3LTA for clearing up the confusion.

Press ~ to open Console

coc RiftenOrigin

Once in Riften go speak to Shadr about working in the stables.

Now you can enter
setstage TGLeadership 200

and then the achievement will pop