Shooting a wedding isnt for amateurs. If you're shooting for a family member and they choose not to hire a professional, then that's their fault and can not hold you accountable for shots that are garbage. Weddings only usually occur once in someones life and having someone that has never shot one to capture their moments is a little crazy in my opinion, unless money was an issue. But even so they say they are paying for half of your 800 dollar camera? Why not spend a few more hundred and hire a pro photographer. But someone that has never picked up a DSLR trying to cover a wedding is a little on the

side.
Either way, post your questions specifically asking for certain things and Ill try to answer them for you. Ive shot several weddings.