One additional piece of information about Course Lock. The Phantom should register the direction the nose is pointing during the startup evolution. Thereafter, the Phantom controls will be oriented the that same way during flight, so that right stick moves it to the right of the original direction, forward stick moves it in the original direction it was pointing, etc., regardless of the direction the nose is pointing during flight.
For example, you might want to take a video of something by passing it. So, you can lock in the direction of travel so that forward and back stick makes it move forward and back, while at the same time the nose is pointed off the direction of travel by 90 degrees.
You can force both GPS location fix (for HL), and the nose direct fix (for CL) at any time, usually before takeoff. How to do this is explained in the manual.
This is just to get you pointed in the right direction (so to speak). Don't take my word for it - go to the manual and read up on this, and DJI has an excellent video explaining the modes of orientation control.