This is not the place to write about mapping, just saying.
FYI:
To open a map, you simply you drop the files into the corresponding folder in your CS2D root folder (eg:. Happytown.map goes to maps folder, tileset goes to gfx/tiles folder, etc)
Then you simply start CS2D and there is a menu called Editor, you just click on that and look for the floppy icon with arrow down.
Pick up the map name in the list and load.