Cyberpunk 2077

To unlock these achievements you need to have at least 3 DAEMONS unlocked. That doesn't mean you have to summon three infernal beings, but simply have unlocked some skills in the INTELLIGENCE section (under Breach Protocol).
You start with 1, the one that reduces the usage of RAM for the quickhacks, so you need other 2. The first 2 you could acquire from Intelligence are the 1) MASS VULNERABILITY and 2) the one who shuts down all the cameras in a network for three mins.
Once you got three of them, find an enemy, hold LB and start BREACH PROTOCOL.
The usual minigame will show up as usual: now you need to activate all 3 of them at the same time. It may require a bit of practice to form a code that will unlock all of three of them at the same time without failing, some codes are easier than others and that is up to the RNG god.
Try to upgrade your operating system (ripperdocs), the higher the better, it gives you the possibility to insert longer codes. Thanks to DarqStalker for mentioning it.
A little tip I can give you is that before starting to insert the numbers, try to form a mental path with all the numbers, it'll help in not making any mistakes. As soon as you insert the code that activates all the Daemons, the achievement will pop.

Happy hunting!

To unlock this achievement, you need a minimum of 3 daemons uploaded. The first cyberdeck you receive through story progression is the Militech Paraline. It has two base ram, four buffer size and two slots. The main concern for this achievement is the buffer size. Four really doesn't cut it. Visit a ripperdoc and look for a cyberdeck with a higher buffer size. I found the Biotech MK.3 with 10 base base ram, 7 buffer size and 5 slots for 25k eddies.

Now for the daemons, go to the character tab and select INTELLIGENCE then the BREACH PROTOCOL tab. Put a point in MASS VULNERABILITY AND BIG SLEEP. You will have one daemon unlocked by default with the cyberdeck. This puts us at three daemons.

Now it's time to get the achievement. Use BREACH PROTOCOL on enemies or cameras. Make sure there are several enemies along with cameras and other breachable stuff nearby. There should be three rows underneath SEQUENCES. If there are less, then move on till you get three. Once you have three, go to https://cyberpunk-hacker.com/ and input the information being requested. 1. Buffer size 2. Enter Code Matrix 3. Enter Sequences. It will solve the best path for you.

Here are screen grabs of the solver and what the solved problem looks like. I couldn't figure out how to insert screen grabs unless they were Xbox screenshots.

https://imgur.com/gallery/UGsz1gE

Version 2.0 Guide: The Breach Protocol system & its Daemons are substantially changed in Version 2.0

The achievement is unlocked when you solve 3 sequences in a breach protocol code matrix thereby uploading 3 daemons into the network. Search for an access point designated by a unique symbol. Access points are frequently found on antennas but can also be a console on a wall. Press to begin breach protocol. You are constrained by a time limit but the timer does not start until you select the first code. You must match your selections in the code matrix to the sequences on the right. Matching 3 sequences without exceeding the buffer limit and within the time limit pops the achievement.

The graphic below illustrates the breach protocol code matrix with a solution for the sequences for the 3 daemons listed: Basic datamine, advanced datamine, and expert datamine. Additionally, an insert on the bottom right shows the symbol for the access point.

Most access points require an intelligence skill check before you can gain entry. The lower the skill check the easier it is to solve the sequences for the daemons. The Watson District, where you start the game, has some of the easiest access points. As you progress, the skill checks increase and some are as high as 20. In other words, you would need to max out the intelligence attribute to access them.

@landmineshurt in the comments has some valuable tips: "As long as you don't start the timer, you can jack out and back in to reload the matrix and get a better roll. I do it all the time because even with 8 spots, some of them can't be solved for all three. Also, take the early perk that reduces length required by 1, which reduces the length of ALL THREE sequences by one." The perk referred to is the Forcekill Cypher. It's a rookie level perk at the very bottom left of the intelligence skill tree.

Lower skill check points feature shorter daemon sequences and smaller code matrices. The graphic above is based on a screenshot of an access point with an intelligence 10 skill check. The code matrix is a 7 X 7 grid. The length of the sequence is a variable. I made a save before this access point. Reloading the save gave me different sequence lengths each time. Usually, it provided sequences of 3, 3, & 4. When the luck of the draw gave me sequences of 2, 3, & 3; I solved the matrix.

If you back out of the access point before you solve any of the sequences, you can try again. However, the time is shortened. Thus, it is better to reload a save made just before gaining access. You are permitted some incorrect choices. Some sequences cannot be solved without an incorrect choice. Such a choice moves the digits of the sequences one space to the right in the code buffer. The larger the buffer—dependent on your cyberdeck—the greater your chances are for solving the matrix.

Not all code matrix/3 sequence combos are solvable. Reloading the save file made just before connecting to the access point is often necessary to provide you with a code matrix/3 sequence combo that is solvable.

Version 2.0 changes. This achievement has increased in difficulty substantially from earlier versions of the games. Previously, one could execute Breach protocol against enemies or cameras during combat. You were provided with one combat daemon automatically: Ice pick. You could get additional combat daemons in the Breach Protocol perk tree such as mass vulnerability. The combat code matrices were easier to solve than the access point matrices. They had smaller code matrices and shorter daemon sequences.

In Version 2.0, Breach Protocol opportunities are greatly reduced. There is no longer a breach protocol perk tree. You are confined to hard wired access points: antennas, wall consoles, some select computers, and so on. However, the achievement need not be difficult. Search for low skill check access points in or near Watson. Get the best deck available to you with respect to buffer size. Most importantly, make a save before you access the network. If you are accessing a low skill check access point, RNG will, eventually, work in your favor and give you simple sequences to solve--as it did for me in the example illustration above. If you are lucky, two of the sequences will be identical which means that you upload three daemons by inputting two sequences.

Online minigame solver: If you need help with the minigame, you can use the solver at: https://cyberpunk-hacker.com/
The solver is not perfect. After you've solved a few sequences, you'll find it's easier to solve them on your own rather than go through the tedium of entering the code matrix and sequences into the solver. Nevertheless, the solver makes it easy by requiring you to enter only the first digit of a code. Entering B, for example, automatically results in an entry of BD. The default solver shows a 6 X 6 code matrix but you can enter smaller or larger matrices. The solver often struggles even with simple solutions but, if you rely on good RNG by reloading saves, you'll eventually hit on a combination within the capabilities of the solver.