Uplay can be accessed from the main menu. Once you have registered for Uplay, you can 
earn Uplay points by completing the indicated tasks:

10 Uplay points: Successfully complete Sequence 2.
20 Uplay points: Successfully complete Sequence 6.
30 Uplay points: Successfully complete Sequence 12.
40 Uplay points: Reach Level 20 in Multiplayer mode.