To customize your sled:

1. Head to the garage by tapping the sled icon on the top of the screen.
2. Scroll to the sled you want, and pick the part you want to change.
3. Pick your favorite style and tap the paint bucket to pick a color.

Customizing your rider follows the same procedure, but on the top of the screen you tap the coat hanger instead. 

Locked styles can be purchased using Silver or Gold.