To begin the assembly, we'll attach the 2" wide front edge to the bottom shelf. Align the two parts and make a mark across both pieces with a pencil every six inches or so to denote the locations for some biscuits. Then, using your biscuit joiner, cut slots for some #10 biscuits in both the front edge of the shelf and the back side of the 2" piece. Evenly distribute a small amount of woodworking glue in the slots, place the biscuits in the slots of the shelf and attach the front edge. Clamp the edge in place using some woodworking clamps and set aside.
While that dries, we'll attach the square rings to the racks. Place each rack face down on a table with the ring on top and attach with finish nails.
Next, we'll attach the two sides of the carcase to the bottom shelf assembly you put together above. Align the parts and mark slots for biscuits in both the sides of the standards as well as the ends of the bottom shelf. Apply glue, insert biscuits and attach the two sides to the bottom shelf, again using clamps to hold the assembly together. You may wish to use a couple of finish nails through the sides to help hold the bottom shelf. Set this assembly aside to dry for a while, while we move our attention to the wine glass racks.
Place the small shelf (for the bottom wine glass rack) upside down on your shop table. Position the 1" strips in their correct locations as shown on page 3 of the free woodworking plans you downloaded in step 1. Attach them to the shelf with some glue and finish nails. Next, attach two of the 2" and one of the 3" rack pieces to the strips with glue and finish nails, again as shown in the drawing on page 3 of the free woodworking plans.
Attach the wine glass rack pieces to the under side of the top shelf in exactly the same manner.
Allow the glue on all of the parts to cure before proceeding to the final step.