- Top Air: typically spams t1 until bottom air gets t3, but not necessarily; in charge of getting radar, and also SMD in time before enemy Eco can destroy everyone in top
- (Upper) mid: goes to the upper lane in mid. Land focus, but will often start with air fac to get engies in mid in time. Playstyle depends on individual.
- Mid: handles the "true" mid lane, his survival often depends on Navy even if he wins his slot. Can and probably will start with air fac like the other mid player
- Navy: as the name says
- Eco: as the name says, is supposed to handle late-game and is responsible for winning (or losing) the match when it gets to that stage
- Bottom Air: in charge of getting t3 air faster than the enemy team and possibly win the game or cripple them with strat(s), or at the very least getting asfs out in time for enemy strats; also in charge of radar for bottom. Might give t2/t3 engies to eco/rest of team to help, but this will necessarily delay his own progression.
Variations and other strategies are always possible (t2 air spam to win, double/triple navy, eco/navy ACUs to mid.), especially when playing with friends/people you know (also see: stacked teams, a reason why most mid-to-high level games use opti).
I'll let someone else tell you about the True Masters because I wouldn't know.
One important thing to know is who gets what rocks: it's generally rude to eat rocks that don't belong to you (not to mention entirely harmful to your team on the whole), and I have seen high level players just quit minutes into the game because their rocks were being stolen/trees knocked down. If you prepare any pic with the rocks marked I'll tell who they belong to.