After the 'trial run' of the first event, which does grant you the XP you earn, you'll get to pick your first car from a choice of three. After you've done that, you're then on to Career.
You'll have the first three races unlocked, each having 3 objectives tied to them:
Finish the Race
5 Clean Overtakes within 01:00 Secs (the text says Secs, but it means 1 minute)
Master 3 Corners
Top Speed of 120mph
8 Clean overtakes within 02:00 Secs (the text says Secs, but it means 2 minutes)
Master 5 Corners
Lap Time of 01:22
Lap Time of 01:24
Lap Time of 01:28
Complete all three objectives for one race at this achievement is yours.