In the singleplayer game, I believe you start out with just the yellow stance. As you progress through the game you gain access to the blue and red stances. If you check under force powers on the datapad menu, it will tell you what stances you have access to.
In the multiplayer game, everyone starts with the blue stance. You can then spend points to aquire the yellow and red stances.
Hope that clears things up a bit...
And don't worry about being a noob. Everyone
was a noob at one point