Replying to Box help...

Hey, my friends and I were going to build a box...so far we're gonna get a UMHW topsheet and some 2x4 studs at home depot or something...so yeah we need some help with like the structure of it. We were planning on just making a solid box design but we arent sure how...possibly just make a frame with 2x4s I guess. I guess we have a decent plan for the structure of the box, but we're not sure about coping...would you guys recommend something for coping? I found some steel angle things online for really cheap but I'm not quite sure how to attach them to the box, haha we are pretty lost on that part