Various jobs of the game:

Tank: CC the frontline to engage and counter-CC when engaged. Mage: long-range waveclear and siege Assassin: Burst the mage/ADC and splitpush

Marksman:

1. Waveclear
2. Siege
3. Burst the enemy team
4. Take objectives
5. Drain tank
6. Clean up

Fighter: Sustained damage, 1v1, and splitpush Bruiser: Counter-CC, 1v1, engage, and splitpush Support: Babysit the marksman, engage, counter engage, peel for the marksman, give the marksman kills, heal the marksman, ward for the marksman.

I miss anything?