That's a combo right there :)
Untap, upkeep
Guide and Combatant attacks, Guide gives Combatant flying, I assume you take it since you just have a C open (we can back up if I'm wrong :) ) so that's 3
Island
Steadfast Sentinel
Done
Spidey: 20
Hand: 11
Battlefield:
(T,T) Island x2
(T) Mt...