1) Export your map in map maker
2)Go to the exports folder and collect all the files for your map, copy them. If you have custom terrains, particles or the like, collect these from your media folders.
3)Paste all the map files into a new folder that you can name after your map.
4) Zip this folder.
(WinRar if you need a zipping program) To zip the file, right click and hit "add to archive".
5) Upload the zipped file to mediafire by signing in, and then hitting the upload button on the left hand side of your screen. Click the little plus sign to add files.