Since your using Mediafire.com you should see a screen like this once you sign in:
Click the file you want to share like so:
It will take you to another page that looks like this:
Like WhiteLightHeart said you copy that link up there by right clicking it and selecting the "copy" option. Then you go to whatever site it is you are using for your group and paste it there, or paste it here on the forum in a new topic in a section of the forum like the Map section:
http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&board=21.0.You could also inbox the map to friends. The number of ways you can share it are infinite it's up to you how you share it.
If you want to share the link in game though you might want to shorten the link a bit so you can type it easily into the chat box. You can shorten the link by copying it and going to tinyurl.com. You will see a page like this:
Paste the link in the area circled and click "Make Tinyurl!", Once that is done you'll see this page:
Type that little link that is circled to your friends in the chat in game and then they can find the download to your map
Hope this helps. I can't explain any better than this.
