How do you get a weapon from category I in commando 2?

If u look at the top of the screen u can c letters a b c d e f g h i j click on a letter to c the weapons in the section. Click on a weapon to place it in an empty section in the coloum of circle to the side once it is full you cant put in any moer weapons. The ones already filled with a pistal and a knife can not be deleted.