If you select the airport as your only waypoint then you are correct: using the bearing (BRG) given as your heading will get you to the airport but you will not be lined up with the runway.
When planning your flight, you will notice that there are long, skinny, triangular paths that represent the approach to the runway. Sometimes there will be a waypoint available at the beginning of the approach. Use that one as your first waypoint and then the airport as your second waypoint "Add To FPL".
To go into a little more detail... Sometimes flying directly from your origin to the approach for your desired runway will require you to make a sharp turn. In this case I find it is better to add an extra waypoint- one before the approach. By doing this you can keep your course changes to 90 degrees or less.
And lastly, you may find that (especially at large airports) the waypoint named for the airport isn't even on the desired runway. If not, look for a waypoint available at the beginning of the runway.
Have fun and let us know how it goes!