I don't feel like typing alot right now but I will point you to some articles to read up on.

Well you would need to Cycle your tank.

You can use stones but gravel is easier to clean if you have a gravel vaccume. Here is a page about cleaning tanks: Clicky

Dividing is easy Clicky. I used plexi glass and I didn't use the back wall thingy for the filter like the article suggested. I did it like how they show the plastic canvas ones but used plexi glass...if that makes sense. You will also need to slow the current down here is an easy way: Clicky

You will need one 50W heater and a thermometer. Bettas need low 80's--high 70's *F.

Look around at the article here: http://www.petfish.net/kb/1/

I found it so much easier to have a divided tank as it was less work then have different bowls to clean out 100% weekly.