How do u make NPC respawn over time?

SOLVED

I want zombies to respawn every 2 minutes or so to attack a fort in a map im making. how to i do this? is the a tool for it? if so wut is it called? plz post.

Thank you

-snip-

Why the fucking snip? What if somebody else want’s to know.

Jesus christ, have a box.

i didn’t have the answer, i didn’t see the “SOLVED” text and i edited

[editline]02:59PM[/editline]

what i wrote was

Ownd