Do you mean the gate to Cape of Distant Worlds or another map?
If it's a gate to Cape of Distant Worlds then go to Destination Postion in the Map Maker and change X, Y, and Z. It usually helps to put an object where you want the portal to be because you can just copy off the object destination. Yaw is the direction the portal is facing. Face the way to want your portal to face and copy of the Yaw from the bottom right corner of the map maker.
If it is a gate to another map that you creating you just click 'New Gate' and type in a place to where it leads. Then place it where ever you want just like an object.
Maybe you can take a screenshot?
I don't know, I hope this helped.
~~Allie