Here is the full list of all 22 The Timeless Child - there are Prologue achievements.
Complete the prologue playing as Emily Wells
Find and read all sheets
Listen to all George Wells tapes
Help solving Greenhouse Puzzle without ever making a mistake
Ring the Time Bell for the first time
Solve Paintings Puzzle without ever making a mistake
Solve School Puzzle without ever making a mistake
Complete the prologue playing as Chris Hunt
Try to access the basement playing as Chris Hunt
Solve Books Puzzle without ever making a mistake
Open the map for the first time
Play with a friend for the first time