While the glue sets up on the cabinet doors and dovetailed drawer, we'll turn our attention to the base of the cabinet.
As noted on page 4 of the free woodworking plans you downloaded in step 1, you'll need two pieces of 1x4 ripped to 3" width and cut to 19 1/4" in length for the two sides. You'll also need one 3" wide piece at 33" for the back and another at 36" for the front.
TIP: Keep in mind that this front piece will be the only portion of the base that will be visible, so if you're making a hardwood cabinet, you'll want to use hardwood for the front, toe-kick piece of the base.
Connect the four pieces as shown in the detailed drawing using finish nails or a pneumatic finish nailer. No glue will be necessary on these joints.