When Conclave Sledge-Captain enters the battlefield, its backup ability triggers three times.
Resolve the first trigger, putting a +1/+1 counter on the creature with power two or greater, and causing it to gain the printed abilities until end of turn.
Repeat step 3 for each remaining trigger.
Deal combat damage with the creature that was targeted in step 3, triggering the creature's ability three times, putting three +1/+1 counters on the creature for each damage it dealt.
At the beginning of your next upkeep, Mayael's Aria triggers, causing you to put a +1/+1 counter on each creature you control, gain ten life, and win the game.
Results
Win the game at the beginning of your next upkeep.