how can i upload a map?

First you have to go to Additional Options, there you will have a button called "Manage Attachments" in that you have to add the File and once its added give "Insert Online" and then the File will be Attached to your Post.

Or you can use anyother websites like [URL="http://uploading.com/"]uploading.com[/URL], [URL="http://bayfiles.com/?"]bayfiles.com[/URL] , etc and upload it and Share the link here.