Every comment in this thread is spot-on.
I’ll add mine, as I have made a number of replacement tabletops for power tools: Radial arm saws. The basic process, emphasis on MOST BASIC, would be the same and I suggest you check out the DelphiForums blog for radial arm saws in order to learn how to produce a worthy, flat and true top. But understand that those tops are simple rectangles, there are no pairs of miter slots, nor a precise cutout for a blade insert. These tops are made from a double layer of MDF or Baltic Birch plywood.
Having made several RAS tops from various solutions, I will share that it is incredibly easy to botch it. What happens when the job gets botched? You are forever doomed to have imperfect cuts, imperfect joints, imperfect glue-ups, etc. Every single stick that is cut will be off just enough to prevent things from working right and sometimes they even won’t be able to be assembled...expensive wood wasted again and going in the trash. Yep, sad, sad story.
Given that there are scores of table saws continually available on Craigslist for not too much cash, how much is your time worth to you? Realistically, since this is your first tabletop fabrication, an honest estimation of the time you’ll probably need to complete a proper top would be in excess of 20 hours. If you pay yourself $15/hr, that works out to $300...if you get it just right on the first effort. For $400-$500 you can start getting quality cuts within a couple of tuning hours, no surprises.
You are the proud owner of what’s known as a “basket case,” I wouldn’t get too emotionally attached to it since there are so many other equivalent or better saws out there for not a lot of dough. Cut it loose.