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.
Find Rodric's forge
Fully upgrade the equipment
Enter into the 5 alchemist carts
Find 13 curiosities
Find 6 flowers
Fully upgrade the sling
Enter through the main door
Find the tomb
Save a soldier
Play hide-and-seek
Complete all chapters
Complete chapter 16
Complete chapter 15
Complete chapter 14
Complete chapter 13
Complete chapter 12
Save the dying
Complete chapter 11
Complete chapter 10
Craft 100 ammunitions
Complete chapter 9
Complete chapter 8
Complete chapter 7
Complete chapter 6
Complete chapter 5
Complete chapter 4
Complete chapter 3
Complete chapter 2
Complete chapter 1
Complete the aiming training
Find all the flowers
Find all curiosities
Find all the gifts for the orphans
Find a lunch for Hugo
Stay with the captain