The first part of the cabinet to be assembled are the sides, top and bottom. The front and back go on later.
Before gluing up the cabinets I lay everything that I'm going to need out on a large flat level surface. Once the glue bead gets laid down, the clocks ticking, so you'll want to move with some speed and efficiency. Having an extra set of hands for the step really helps, but it's not a necessity.
Lay a thin bead of high quality wood glue (I like Titebond
myself) along the edges of all adjacent sides. Be sure to spread extra glue inside the holes for the biscuits. I use a chip brush to paint the glue into position and spread the bead evenly into a 3/4" strip.
Insert the biscuits into the slots, being sure to push them all the way down. Any biscuits that don't easily fit into the slot should be discarded and swapped for a new biscuit--sometimes the biscuits swell slightly due to moisture and humidity.
With the biscuits in place and glue on all of the adjoining surfaces, it's time to assemble. Join edges to faces and construct the cabinet.
I use many many clamps to pull the cabinet tightly together and apply uniform even pressure to the joints.
With the edges glued and the clamps loosely in place, now's the time to square everything up. Using a tape measure and the clamps, measure the diagonal from corner to corner of the square you've just created and adjust the clamps until they are equal. This means that the box is perfectly square. See the photos below.
Before the glue sets up, it's also a good time to make all of the panels flush with each other. Use a dead blow hammer and a block of wood to knock all edges flush.
Apply a sufficient amount of clamps and wait for the exterior walls of the cabinet to dry. As you can see from the pictures below, pipe clamps are great for this purpose, and if you've been needing an excuse (or two) to buy some, 42" tall tower speakers are good ones.