You can press the Test button but then your only a default lion and the sky stays the same.
In Map Maker with your map loaded there is a check box called "Has Portal" After checking that box place an object like a rock where you want the portal to be. Copy the rocks X, Y, Z coordinates into the portals X, Y, Z coordinates then save it (You can remove the rock when your done. The portal isnt exactly where you put the rock so be sure to test your map to see where it really is)
Log into the game and choose a character, then go to Cape of Distant Worlds and all your map portals will be there, jump through the portal and your there.
Be sure to post your next help thread on the Game Help section of the forum, no help threads are allowed to be here.