First on the loadout screen you need to create a new loadout and name it. Then you can right click on middle column to add bombs.
As far as waypts. make sure to have 3 perfectly in line with each other (4,5,and 6 in pic). You need a waypt before and after bombing waypt to create your bombing run.
5 is where the advanced waypt action is added and you put arrow in middle of area you want to bomb. Make sure this waypt is far enough from target 2.5 miles or more.