Unregistered

hi i really need help on my map of underland i cant figure out where to put the western red desert. so there for i can not get through to the door that leads you there. on the map i noticed that on the background of the piece there is a picture so i matched it up with the background on the map that looked like it but it wont connect to any pieces it looks like a conner piece so if you can help me please do i have been stuck for a while now! PLEASE HELP ME!