Simple enough question :~} It depends on how you want to proceed. You can either find a partner and start working toward competing in amateur competitions or you can find a competent pro and do pro am.

Actually either way the most important thing is to find a competent instructor because you'll need one to improve your skills. To find one you like go to a couple of comps and watch the pros until you find one who looks like a good fit. Then go sit in and listen into one or two of his/her lessons to see if they teach in a way that is compatible with how you learn. If you can find a partner it's great but it isn't mandatory and some people don't want one at all. It is up to you...follow your bliss.

As Belle said, you don't need a partner if you go Pro-Am. However, this is an expensive option. If you want to compete as an amateur, I don't see how you can do that without a partner. You need to train together and have good working relationship. There has to be some chemistry if you are dancing latin. So, yes, find a partner, then find a pro who teaches competitive couples.

Yes...very expensive. It will be cheaper to go amateur and if you can it's smart. But then comps are expensive no matter how you look at it.