Hammer Editor: How to make NPCs spawn at certain places and times

I am making “The next best map” and I want to make it so that when a player enters a certain area, a fast zombie spawns somewhere in the other room ferociously charging at the player. I believe algrebraic codes are involved but what is the easiest way to accomplish this?

I do think they are npc_npcname for example npc_zombie, but not sure, though. As for a time, spawn the NPC and make a brush-based trigger_once, put it on the “other room” and set it to spawn the NPC (assuming you know how outputs work), however I do think you need to set the NPC not to spawn unless triggered.

And please, for the sake of all decency, DO NOT call a map “The next best map” that is a incredibly moronic name.

Ha ha ha, I just get a little cocky when I am editing this. Thats not literally the map name, I just wanted to give people the humorous idea. I have never done an output but I will experiment with it.

Outputs are pretty east to get the hang of if you are not a retard. Just give it a name, pick the entity which It will control, pick under what conditions to activate (OnStartTouch) and chose it to spawn. Thankfully whenever you click the box, it shows you all correct inputs you can give the target entity, which will make it a whole lot easier.