How can you make "All Purpose Flour" using home ground wheat?
Typical all purpose flour does not include the germ of the wheat, so if you would like to mimic the stuff from the store, you need to grind wheat without the germ (source).

By using hard white wheat and a very fine grind, I have for years made a flour that operates very like whole wheat pastry flour, which can often be substituted for all purpose flour in recipes.  To make this same flour suitable for bread I add vital wheat gluten.