To add on what to bloo said...
Once you're finished with your map in map-maker, hit the "export" option. This will export your map into shareable files that will be found in your exports folder. Basically anything that it says it exports (FHM. FHO FHS/FHW files), you need to upload (usually most prefer to group files together in a zip folder) these files, and then share them with your friends. This will make your map accessible to other players.
