Populate X times. (To populate, create a token that's a copy of a creature token you control. Do this X times.)
Any abilities that trigger while you’re populating won’t be put onto the stack until after you’ve finished populating X times.
Each time you populate, you can pick any creature token you control to copy. You don’t have to create X tokens that are all copies of the same creature token.
If X is 0, you don’t populate at all.
The tokens enter the battlefield one at a time.