Here is the full list of all 35 A Plague Tale: Innocence achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Complete all chapters
Complete chapter 16
Find Rodric's forge
Complete chapter 15
Fully upgrade the sling
Complete chapter 14
Complete chapter 13
Complete chapter 12
Find 13 curiosities
Find 6 flowers
Save the dying
Craft 100 ammunitions
Complete chapter 11
Fully upgrade the equipment
Complete chapter 10
Complete chapter 9
Enter through the main door
Complete chapter 8
Find the tomb
Complete chapter 7
Complete chapter 6
Complete chapter 5
Complete chapter 4
Play hide-and-seek
Complete chapter 3
Complete chapter 2
Complete chapter 1
Find all the flowers
Find all curiosities
Find all the gifts for the orphans
Enter into the 5 alchemist carts
Complete the aiming training
Find a lunch for Hugo
Save a soldier
Stay with the captain