Welcome! Your best bet for posting maps is to just use other map posts as examples. Take a look at how everyone else does it, and try to model your post after the.m. Enjoy your stay!
Ok tell me if I'm right I go to bungie.net, log in, then go to my file share to get the pic of my map.
You take the picture of the map in theatre mode, preferably more than one, then it will be under recent screenshots on your bungie.net profile. Each map you post needs atleast 1 secreenshot / video, and it must be embedded Welcome to forgehub by the way