OK, first off back country camping is off the beaten trail. It is not "CAR CAMPING" or at a campground. Yes, there are trails and it's safe with proper preparation. But you need to carry all that you need on you. It's a pack it in, pack it out philosophy. No trash cans, no running water just you and nature. It sounds daunting buy even a beginner can do it with the proper equipment and training. If your friend invited you then he's probably done it before (lets hope).
Check out a local outdoors supply or a chain store like REI, Big 5 Sports, Sports Chalet where majority of these business's will offer classes you can take for a small fee or FREE. These classes will get you "OUTFITTED" properly from qualified people from top to bottom inside and out, they will teach you what books to read, what type of sleeping bag and tent and everything else to pack, how to pack it all, what to use when and where and why, navigation (compass), cooking, water purification, trail and camp etiquitte, and of course survival skills. I'm sure your friend already knows much of this so listen to him

Remember no littering and respect mother earth. Good luck, be safe and have fun!!!!!
You always will have an amazing time for sure when you prepare properly. Let me know how it goes. Where you going by the way?