Random Spawning

I have 3 spawning positions for my monster.
I need to randomise such that my monster will spawn at either 1 of the 3 positions.
The monster will only stay there for 10 secs. After 10 secs it will spawn randomly.
I’ve already placed an empty movie clip at each of the spawning position.

I’ve did a timer, but i dont know to to reset for another respawn.
Can anyone roughly tell me how to randomise and attach my monster movie clip the empty movie clip ?

Thanks