Don't pay attention to the cave bit just follow the first part under the first pic it explains it Shae
This part:
"You must connect it to Cape of Distant Worlds. To do this, click the Map tab and check the "Has Portal:" box. "Destination Position:" tells the game where you want to spawn or arrive in your map. Remember, the portal to Cape of Distant Worlds appears directly behind where you start! Zoom down to ground level and point the mouse on the ground where you want people to start when they enter your map. At the bottom of the screen there are several numbers in a narrow box. Write these down, memorize them, round them to the nearest whole number, whatever you need to do to remember them. The first number goes in the "X:" box (lol xbox), the second into the "Y:" box, and the third into the "Z:" box. If you want to be facing a certain way, turn your camera to face that direction. The last number in the box tells you the Yaw, or how much you turned. Add that number into the "Arrival Yaw:" box. If you want to face directly South, leave that last box blank. A helpful tip: If you spawn on an object, add 10 to the Y value to keep from falling through it. Don't forget to save."