Help??? Shooting a Wedding tomorrow!?

I need some advice and help. I don't have a professional high dollar camera but I have a good working camera (a Kodak EasyShare Z812 IS) the wedding I am shooting is a very small non-fancy wedding for a friend and I am doing this for free. I am wanting to make sure I get every lil shot for them and make this day special! But I am really nervous because this is my first wedding shoot...So I need as much advice as possible! I have done this friend's senior photos and her& her fiance's engagement photos. I'm not super professional yet but I am in the process of becoming a professional. I didn't ask to do their wedding but they asked me to do their wedding for them. I am just nervous cause its my 1st wedding and have been hearing how people get crazy and cranky about weddings, which is understandable because its a special day! I am just needing any advice from people who experienced photographing weddings. Also It seems to be a lil difficult cause I wont be able to see the setup til an hour before the wedding because they havent been able to setup the wedding yet, and needing help on what lighting I would need to get thats cheap and fast to get just in case. The wedding is also in the same exact room the reception will be held at, so does anyone have tips on not letting people try to get in front of you while you are trying to take photos of the bride,groom,family, and wedding party? I have a friend who is helping me out on backing me up with a secondary camera at the wedding so this will help tons! Just need advice people! No negative comments til you seen my work.