Hi, you could do that with that top, is that the one you have? If yes, and I were doing it, I'd remove the center Ttrack, cut the shape of the router plate out, then add a second layer, preferably of Baltic Birch ply or even MDF will work to make sure it stays flat. Cut the opening an inch smaller than the opening for the plate so you have a half inch ridge to keep the plate from falling in. I suggest you use Kreg's leveling screw devices so you can make the plate perfectly level with the top. See pix.
To start with you can use a very straight chunk of 2x as a fence. Cut out a small area in the center for your bit to fit in. An inch and a half deep at least, two inches high. You can add a strip of wood to back, bottom edge so you can easily clamp it to the table with modest sized clamps. You can glue these in place, but make sure the face of this board is 90 degrees to the table top. If you have a combination square, you can use it to check for square. Personally, I like a taller fence, so consider a 2x6.
You can leave the table open to start with, but it's pretty easy to enclose that table with half inch ply, then you can add shelves and drawers, which will be great learning projects.
Make sure you buy a mounting plate made for the router you have first. There are various sizes. I have a leftover Rockler plate, and it is a tad smaller than the one I replaced it with. They come pre-drilled for the more popular routers. I prefer the aluminum plate myself.
I found a picture of the Kreg table, which is very much like the one in the link. It has a commercial fence. Have fun with it. I really enjoy using the router on a table far more than freehand.
Very last thing, WEAR A GOOD DUST MASK!!! Sawdust is insidious, and when you enclose the base, you will want a chamber below to catch the dust, and you should also plan to spend enough to at minimum, set up a dust collection setup like the one in the picture. The cone separates most of the dust and drops it into the bucket so it doesn't clog the filter in the shop vac. Get a BIG shop vac. The Dust Deputy (cone and bucket) is not very expensive. And I have found that Rockler makes hoses and connectors that fit. If you mix brands, they often don't fit.
The more I do, the less I accomplish.