(Taken from my Xbox guide on TrueAchievements)
For this one, you have to beat all levels in any world, each world has 3 levels, except for Finding Dory which has 2, the worlds are:
Toy Story
The Incredibles
Cars
Ratatoullie
Up
Finding Dory
If you beat all episodes of a certain world and the achievement doesn't pop, i recommend just playing through the game normally until it pops, this game is quite glitchy with achievements so i don't recommend going for certain achievements until all the easy achievements are unlocked, as it will take longer for all of them to pop, those being:
Bronze Away! - Win your first bronze medal, alone or with a friend.
Fast Learner - Complete your first episode, alone or with a friend.
Silverado! - Win your first silver medal, alone or with a friend.
You might get more than these 3 depending on what levels you play, as some have specific achievements you unlock them on, those being:
Daycare Dash (Toy Story)
Fancy Drivin' (Cars)
Canyon Expedition (Up)
Save Metroville (The Incredibles)
So i recommend avoiding those until you get the 3 previous achievements and True Adventurer