Forza Horizon 5

Missions are in the menu and how you progress through the expansion. I unlocked this after completing the A class qualifier. Before starting that event, I won all the B class class events, got 3 stars on all the B class PR stunts, popped my first tank balloon, destroyed my first billboard, and raced from the nexus to dragon mountain in 3 minutes. The other missions unlocked naturally while completing those.