Cut one sheet of 8x4 feet plywood as shown below:

Cut the unused 12"x30" piece into 24  3"x5" blocks.
Lay the pieces out as seen in the second part of the image.
(Pre-drill all screw holes in the following steps.)
Attach B,C,J to A with long screws and glue to form a box half.
Attach E,F,K to D with long screws and glue to form the second half of a box.
Attach all 3"x5" blocks with glue and 1" screws.
Wait for glue to dry.

Attach box halves to panel "I" using four hinges (see pic below).  This is the hardest part of the base build.

Attach clips.
Attach plastic or thick rubber feet.  Mine are made from pieces of a cutting board.  Use strips of a car tire?
Attach four coaster wheels (see pic below).
Close the box and attach the Hasp & Staple.

Drill four 7/8" holes for PVC pipe 2.5" from the edges of the box (see pic below).
Cut the two PVC pipes into two 22", four 28" and four 2" pieces.
Assemble PVC structure using 90 degree elbows, end caps and PVC glue as seen here:

Paint the exterior of the base with two coats of exterior grade paint.
Cut the 7"x9" blue tarp as shown here (parts marked with an "X" are left overs):

Sew the tarp into the tent shape. The tent base should be 7 feet by 30 inch wide.
Extend the middle edges of the tarp to reach the bottom of the base using  two left over triangles.
Cut an incision (entrance) in the middle of the tent from the bottom to the top.
Sew two left over triangles into a rectangle.
Sew the rectangle over/under the incision to form a "door" (see video).
Sew straps to the tent.
Attach the tent to the base by using the straps.

3"x5" blocks are cut from the unused 12x30 piece of plywood. They are used to reinforce the hinges, reinforce the locking mechanism (hasp & staple), reinforce the coaster wheels, make feet and make the box more rigid.  Blocks at least 5" wide are needed for attaching the 4" hinges.  They make the plywood thicker and allow for stronger attachment points.  To make the box more rigid when folded blocks are attached to one side for vertical alignment and opposite sides of the box for the front alignment. (picture below)  Blocks are glued to the box and in addition attached by several screws.

On the top of the tent where it touches the PVC pipes, I sewed a couple of sleeves to put the pipe through.  Leave one side of the 90 degree elbow without PVC glue in order to be able to slip the pipe into the sleeve.

Tent is fastened to the base by eight straps around the perimeter.  Straps are two 1.5 inch wide strips of tarp about 8"-9" long sewn together on the sides.  Straps are adjustable and attach to clips which are fastened to the base about one inch below the edge by two screws.  Clips are made from medium paper clips cut in half. (see pictures).  They are easily cut by tin snips and drilled.  To adjust the strap, you tie a knot and insert it into the clip.