Let's get started!
First you need a map that you want in singleplayer. I am going to use the StarForge map from Shadriss.
Once you have the map instaled in you base folder, open up Jedi Academy Multiplayer.
Open up a solo game of the map you want in singleplayer.
Once the map has started, go to About.
Where it says Map Name and then is says starforge, that is what you want to write down.
Then go into any singleplayer map and open up the console. Type in "map (whatever you map name is)" so in my case "map starforge"
There you go!