finding and replacing the battery in 96 riv

Can someone please help me.. I own a 1996 Riv my battery has gone dead and I don't know where it's located. Also I have been having a heck of a time finding somewhere to purchase it. Is it safe to replace it at home or do I need to take it to a mechanic. Any and all help will be appreciated. It is making me sick seeing my baby just sitting there.
Thank You

The battery is underneath the back seat, if you haven't already figured that out. the back seat should just pull up it's held down by two clips in each corner, pull up on the corners. My little brothers 95 had the same thing, it's kind of a long skinny battery. If your hand you can replace it yourself it's easy, but if you don't trust yourself take it to mechanic. It helps me that I am one so I didn't take it anyware, but it was also a first for me to have it under back seat.

if you have any more questions feel free to ask.

Grant