If you're downloading a repack you'll have all the programs you need to start the server. You will need to download MySQL and Navicat (That's my preferred one) to navigate the Database, to add items, quests, npc's or accounts etc.

All you really need to do is click arcemu-world.exe & arcemu-logon.exe (should be named something like that) and it'll be setup very quickly.

You must then change your realmlist (located in C:/Program Files/World of Warcraft/Data/enEU/realmlist.wtf OR C:/Program Files/World of Warcraft/Data/enUS/realmlist.wtf)

You must change it to "set realmlist 127.0.0.1" (without the quotes "")

If you need any more information, check the post Rikal has linked, and if you're still confused. PM me.