this solution is for the updated version of the game with the level select map.
go to level 4. you have to collect 3 clues and the relic to complete the level. instead, just run and perform parkour jumps while avoiding clues. whenever lara does a leapfrog jump over the gap with the balcony after it, that counts as a parkour jump. also when you veer to the right at the fork and swing on the branch counts. since it's an early level it just repeats a set of easier sections. the in-game achievement will pop up during the level once you reach 20 parkour jumps. i got it between 6000 and 6500 m, but others have reported it taking them up to a few thousand more.