Ok, this is bad, I know... I, er, can't build a box... do I need to mitre my cp sides?  I found L brackets at depot, and was going to use 1/4" wood screws to fasten the sides together via those brackets...going to leave the bottom open to get at the innards...should I screw the top down into the sides?  Will L brackets be ok for the sides?  How are people doing this?  Hard to know which examples will show this, and not sure how to word it for a search...
Thanx!