First of all, no problem! ^^
Take a look at this tutorial:
http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=8872.0Yes, it is very similar. The only difference would be that you are able to place the portal where you choose. The coordinates are for where you want your character to appear in the other map. So you can use the "rock method" I've used in my tutorial.
Load the map where you want to link the portal, put the rock where you want your character to appear. Once you have the coordinates, THEN load the other map, place the portal and type in the coordinates as well as the map name.
It's important to get the coordinates first and make sure the portal put where you want it. I've experienced a glitch where the portal will keep re-appearing after moving it several times. Even after deleting the portal it still re-appears. So then I just place a rock over it x3
Hope this helps!