Closed box baffle?

[nuisance26]

~I'm designing a backpack for my DH and I want it to have 4 separate compartments separated by box baffles. I've never done them before and I'm having a hard time finding any crafty sites and blogs that mention how to do them.
I could make smaller pockets and insert them into the larger pocket, securing at the top, but I'd rather not have the extra fabric weight(using a heavy material)plus I really want to learn to do baffles.
Help?~

[nuisance26]

~No takers, huh? ~