Course selector in a nutshell allows you to choose the direction of which you should fly from a determined reference point (for example, the localizer heading of the ILS).  Heading hold is more for you to fly a certain heading that you have preselected and is not required for ILS unless you wish to use autopilot all the way down (can use it to steer yourself to line up/intercept the localizer. 

So, for an ILS approach, you need two things: the ILS frequency, and the direction of the localizer to be inputed as a course.  The latter can be found on the map (you can easily access this in game by simply going into map and clicking on the airport your landing at), or a published approach plate, and other documents of the airport your flying into. 

Hi Matt,

Lets assume you are east of Las Vegas flying in a northerley direction as you approach the area and you are going to land on runway 25L at Mc Carran Airport.

Your localiser heading will be 255 deg, nav 1 will be setup for the ils for 25L and your doing 90 deg turns, from base leg onto localiser, your not likely to do this but lets assume you will: Your HDG setting will be 345 deg

As you approach the localiser heading of 255 your heading alignment will start to move towards the centre.

You'll needs to be doing approaches onto the localiser at 30 deg offset  or less if your using the autopilot and not 90 deg in my example above and below the GS with APP selected on the autpilot panel.


Another example:
Practice VOR approaches to see the difference between the two.
Imagine you want to approach and overfly las vegas from the south east.

Your heading could be 360, your course selector would be 315 deg.
As you intercept the 135 deg radial from LAS you needle will go towards the centre, you'll need to turn onto a heading of 315.
You'll either disconnect the autopilot from controlling heading and manually fly to the VOR or tell the Autoplito to track the vor on the 135/315 radial.

Try some short flights such as oakland to san francisco international to practice VOR approaches.

If you have fs2004 to hand practice the vor lessons then maybe the first flight of the 737 if your ready for it.

Save your flights as you get further along your flight path.


Hope this helps a little.


regards

Steve