Hi Ace. Welcome to TFP!
I had a similar experience earlier this year when I moved into a home that had a pool and detached spa. I never had a spa before. It turned out to be really easy to take care of.
I'd find the manual for the spa on the internet if you don't have it, to understand the mechanicals and such.
Maintaining the water chemistry is very similar to what's done for a pool except it's on a much smaller scale. The nice part is that you can always dump and refill the water if something gets out of whack and you only have a few hundred gallons of water to replace.
There's a good article here for getting started:
how-do-i-use-chlorine-in-my-spa-or-pool-t10095.htmlAlso, get a good testing kit from tftestkits.net if you don't have one already.
Good Luck!