I would run two 15 amp circuits for your indoor lighting. One for each set of 12 lights. And one 15 amp circuit for your out door lighting. I assume your going to have an inspection done on this work. It's ok to do your own wiring but it's not ok to have someone else do it unless they are a qualified electrician. I would buy an up to date do it yourself book on electrical wiring if you don't have one already. It's pretty easy if you have a book to follow. None of your wiring is going to be very complicated once your box is installed. But you do have to do it right to pass inspection.
