Botany Manor

After you craft the final flower in Chapter 5, you can travel to the gatehouse. I'd recommend completing the Flower Arranging achievement first before you go to the Gatehouse though, it's not missable as you can load back into your game, it just takes longer.

Once you're ready, go to the Gatehouse and post the book in the post box. After the cutscene make your way to the back left corner of the library, interact with the document then then book, place the book on the lectern and achievement pops and game ends.

This guide will walk you through all of the achievements in under 2 hours, timestamps are below the video


ACHIEVEMENTS LIST TIMESTAMPS

0:00 – Intro
0:35 – Chapter 1
1:29 – Windmill Wort Achievement
3:55 – In the Bin & Green Thumbs Achievements
5:25 – Take a Break & Take a Nap Achievements
6:45 – Let me In! Achievement
7:45 – Quack Quack Achievement (Duck 1/5)
8:02 – Chapter 2
8:22 – Fulguria Achievement
12:38 – Boom Achievement
13:20 – Piano Woman Achievement
13:50 – Ash Plume & Crack Achievements
19:25 – Duck 2/5
19:50 – Photographer Achievement
21:50 – Chapter 3
22:32 – Pixie Tears Achievement
28:03 – History Sleuth Achievement & Art Lover (Painting 1/2)
33:20 – Duck 3/5
33:45 – Fixer Upper Achievement
35:25 – Wolfglove and Mountaineer Achievement
39:20 – Lockpicker Achievement
40:45 – Chapter 4
41:05 – Grandma’s Vault Achievement
43:12 – Sapphire Gloom Achievement
47:30 – Who Needs a Plumber & Clean and Tidy Achievements
51:16 – Some chapter 4 clues
55:26 – Duck 4/5
55:46 – Nightfall Achievement
58:41 – Cradle Fern Achievement
1:01:00 – Brook Chalice Achievement
1:04:50 – Chapter 5
1:05:48 – Art Lover Achievement (Painting 2/2)
1:07:00 – Frogger Achievement
1:08:04 – Some chapter 5 clues
1:13:32 – Quack Quack Quack Quack! Achievement (Duck 5/5)
1:14:05 – Help! And Achievement
1:14:55 – Oscilette Achievement
1:18:00 – Fools Emerald Achievement
1:21:31 – Springdance Shrub Achievement
1:28:10 – Botanical Researcher Achievement
1:28:56 – Flower Arranging Achievement
1:40:49 – The End Achievement

there is an epilogue after the credits roll, simply run to the room with Grandma's vault. In the corner, there is a book with a letter on it, interact with it and place it on the podium to end the game and for this last achievement.

100% complete all achievement guide:

Extended timestamps:
00:00:00 - Chapter 1: A Fresh Start
00:03:25 - "Windmill Wort" Achievement
00:04:30 - "In The Bin" Achievement
00:04:45 - "Green Thumbs" Achievement
00:05:40 - "Take a break" Achievement
00:06:05 - "Take A Nap" Achievement (stay on bench for one minute or more)
00:06:30 - "Let me in!" Achievement

00:07:35 - Chapter 2: Survivors of Adversity
00:08:45 - "Piano Woman" Achievement
00:14:15 - "Boom" Achievement
00:15:15 - "Fulguria" Achievement
00:16:25 - "Crack" Achievement
00:17:00 - "Ash Plume" Achievement
00:17:50 - "Photographer" Achievement

00:19:35 - Chapter 3: Peculiar Petals
00:21:15 - 01/10 Paintings
00:22:05 - "History Sleuth" Achievement
00:23:45 - "Fixer Upper" Achievement
00:28:50 - "Pixie Tears" Achievement
00:30:40 - "Wolfglove" Achievement
00:31:00 - "Mountaineer" Achievement
00:33:55 - "Lockpicker" Achievement

00:34:30 - Chapter 4: Botanical Allies
00:34:40 - "Grandma's Vault" Achievement
00:35:10 - 02-09/10 Paintings
00:37:40 - "Sapphire Gloom" Achievement
00:43:10 - "Clean and Tidy" Achievement
00:43:20 - "Who needs a plumber?" Achievement
00:47:50 - 01/05 Ducks
00:47:55 - "Quack Quack" Achievement
00:49:35 - "Nightfall" Achievement
00:52:20 - "Cradle Fern" Achievement
00:54:25 - "Brook Chalice" Achievement
00:55:50 - 02/05 Ducks
00:56:25 - 03/05 Ducks
00:56:40 - 04/05 Ducks

00:58:35 - Chapter 5: Climbing Up
01:00:25 - 10/10 Paintings
01:00:30 - "Art Lover" Achievement
01:00:40 - "Frogger" Achievement
01:06:35 - 05/05 Ducks
01:06:40 - "Quack Quack Quack Quack!" Achievement
01:10:40 - "Help?" Achievement
01:15:05 - "Botanical Researcher" Achievement
01:18:43 - "Springdance Shrub" Achievement
01:21:30 - "Fool's Emerald" Achievement
01:25:30 - "Oscilette" Achievement
01:25:45 - "Flower Arranging" Achievement
01:27:10 - Ending
01:28:00 - "The End" Achievement
01:28:15 - Subscribe!

Full video walkthrough including all achievements, puzzle solutions, and collectible locations! (Timestamps in YouTube Description)