Help adding NPCs?

Can someone please instruct me(in full detail) How to add NPCs into my Garry’s Mod 10? It’s getting really annoying by now. And could someone please tell me how to add playermodels? Tell me if I need any programs, or if I’m missing anything… PLEASE!!!
Kangarii

The instructions are packed in the NPC packs that are worth a damn.

Still, I can’t quite follow 'em. Could someone else please help out here?

[editline]02:56PM[/editline]

Like when I downloaded this TF2 NPC file:

It says to extract to my addons file, I do, but where are they? Not in my spawnlist. Entities, maybe? Explain Please!

[editline]02:58PM[/editline]

Do I need any other files? I’m hearing things about SVN, but I don’t know what it is… Please help!!!