i think it would be better to use the event, 'a unit becomes revivable'
then for the action, u create a countdown timer and name it X (or wateva u want) then start this timer with # seconds, up to u to decide, can also have a formula, e.g. 10 seconds + level of hero x 3 or soemthing.
remember to store the triggering unit in a variable
make a second trigger that detects when the timer expires in your first trigger, and then the action would be to revive (stored unit) at (wherever).
u will need this sort of trigger if you want a revival system similar to dota (since dota revival is based on hero level) and also, optionally u can add the dota revival countdown timer using a leaderboard. this wouldnt be possible if you simply used the wait function, because the wait function is inaccurate.
the revival system for FOC is far simpler, u can go straight from 'unit becomes revivable' to 'revive hero at bla bla' in one trigger