Originally Posted by Princess Penny
I would put in the filter and heater, and let everything run overnight before adding New Guy. Get a thermometer though and check the temp before you put him in ;) That should only take a few minutes.
I'd also suggest picking up a gravel siphon, an API liquid master test kit, and starting your research on the Nitrogen Cycle. Here
is a nice little page to start on, explains the process fairly well I think. You'll wanna do research on how to Cycle with fish however....it will require more frequent water changes and take a little longer then a fish-less cycle, but with a single betta in a 10 gallon it won't be such a huge deal. :)