I need help to know if maps can be imported and how to do it to mcgalaxy.

Maybe?.. You can use this command: /import [path to file in import, or a url file on a web server], if you need couple of worlds, To change the first/main card, write /main [level], replace it with a name of the map you imported, you need to do /renamelvl [level] [new level name], if its name isnt correct/not what you wanted after the import map

In order to import a file you have locally on your system, place the map file in the extra/import folder (create the folder if it doesn't exist)

So for example you may have extra/import/mymap.cw

Then use /import mymap

To import a file hosted online, use /import [url of map]