First, if you've got a wood shop and tools, then you're golden, I don't so I drove to my parent's house to use theirs, plus, they have a built in baby sitter for my 1 year old, so that's a bonus.
ETA after trial and error I found that lining the holes is essential and keeps the bees happy and, well alive!
Step 1: Things to swipe
Babysitter (if applicable)
Piece of dry, untreated wood, (I used a log intended for a fireplace)
Chop saw or chainsaw to cut wood
two pieces of flat wood for the roof
drill press or hand drill
Step 2: Cut the wood.
Step 3: Drill, Drill, Drill some more.
Extra points if you go in there with a dremel tool afterwards and smooth out all their little holey homes. bees dig that kind of attention to detail.