okay. That is alot of questions
Quote: "how can i make like a hallway with smallrooms"
Use a software to build levels. Like Cartography shop or 3D world studio :
http://cartographyshop.thegamecreators.com/
Quote: "how can i have more then 1 enimey"
Use a for next loop to load the enemys and maybe also for checking their AI.
Quote: "how do i make a gun the reloads and has ammo"
Quote: "how do i make hp bars and stuff"
I don't think that you're ready to make an fps game. Start a simple place

You could go to the newcomers corner board. There you will find the perfect tutorial for you. A beginners guide on how to make an fps game.
Here's the link for it:
http://forum.thegamecreators.com/?m=forum_view&t=56770&b=7
Hope that helps
-The Nerd
PanzerGames
here
Free Particle Engine For dbpro :
here