Cut the PVC to the required lengths, being careful to make straight cuts.
Test fit your connectors to ensure they are the correct size and that your PVC pipe cuts were straight.
Insert a 21 1/4 inch piece of PVC into an elbow connector, and tamp it in with the rubber mallet.
Place another elbow connector on the other end of the 21 1/4 inch PVC pipe and secure it with the rubber mallet.
Repeat steps one and two with another 21 1/4 inch length of PVC pipe.
Place one 12 inch piece of PVC pipe into each of the four openings on the elbow connectors you just attached to the longer PVC sections. You will have two halves of a rectangle now.
Attach a "T" connector to each of the 12 inch PVC pieces sticking out of your assemblies.
Connect the two assemblies together by inserting the 18 inch PVC pipe lengths into the remaining openings in the "T" connectors.
Insert each 6 inch PVC piece into the last available openings in the "T" connectors on the base.
Place an elbow connector to the front two 6 inch PVC pieces.
Attach a "T" connector to each of the back two 6 inch PVC pieces.
Connect the front elbow connectors to the back "T" connectors with the remaining 21 1/4 inch PVC length. The arms are now done.
Sew the ends of the canvas into tubes which will fit over the PVC chair arms.
Pull one section of each arm out of its connection and slide the canvas seat on.