Step 1: Materials Needed... Tools Needed...
Some good 1x6 stock, at least 5 feet per house. If using Cedar Pickets, try to find some that are not badly warped and have a uniform thickness. Remember to look for wood that you can recycle!
Indoor/Outdoor wood glue, such as Elmers, nothing fancy is needed.
1&1/4 inch brads, if you plan to use a nail gun, similar sized 16-18 gauge will work very nicely.
Perch is a 1/4 inch twig or other interesting device, such as a Golf Tee, rusty screw, basically anything a small bird would be comfortable perching on.
As basic as a miter box and saw, all the way to a chop saw and table saw if you have them.
Hammer and drill for pre-drilling holes or an air powered nailer (16-18 gauge is all you need).
Eventually, you will need a hole saw, probably 1&1/4 inch, but go to 1&3/8 inch if you have Bluebirds.