
(There are three commands to open a map: "switchlevel", "open" and "start".

To open one of the maps, type: switchlevel GEO_01a. When in co-op, you can open the command console with the `~-key (although this may vary on the type of keyboard you have). The maps starting with "DM" and "CTF" are the multiplayer maps. The Geonosis missions start with "GEO", the missions on the assault ship start with "RAS" and the Kashyyyk missions start with "YYY".

In the Republic Commando game folder (I assume Steam\Steamapps\Common\Star Wars Republic Commando) under GameData and then under Maps you can see all the level files and their names. By the way, if you follow the steps there are some customized maps in the multiplayer screen under co-op, but it's possible to play large portions of the the campaign as well.
