Now, if your DIY experience is starting to inexplicably suck, have a glass of water or two - you're probably dehydrated.
Now that you're feeling better, take heart - you're almost ready for rock-n-roll! Attach the latches to the box so that they will keep it closed when you're carrying it around. If you can find better latches than these, please post pictures - these particular ones are probably the weakest part of the current design.
Latches like these will most likely come with their own wood screws for attachment.