Sorry folks, no step-by-step tutorial (I figured it would take longer and I’d have time to grab the camera). But really, it’s surprisingly simple: using a sledgehammer, just pound the stake that comes with the mailbox kit into the ground. Then, pop the post on top of the part that is sticking out of the dirt (the post has a pre-drilled hole in the bottom to make room for the stake). Boom, post is up. All you have to do afterward is screw the top two pieces onto the post and re-attach the box.
The only thing that I wound up having to correct in the end was to re-adjust the placement of the box itself; I’d started to screw the box in too close to the support underneath which prevented the hinge from opening all the way. I moved the box an inch forward, and I was back in business.
The house is really coming together, don’t you think?