Lol, congrats on using 2k3, but perhaps this isn't for you.
Well, to make a map, you right click in the lower left section of the 2k3 screen, where the other maps are, and select the option to make a new map.
To get rid of the water tiles, just click a different tile (in the top left section), the select the "fill" button (looks like a bucket of paint) and then click the any water tile on the map.