Decide size, shape and height of stage and size of sections. Take into account storage and transport needs and availability of stage crew to handle heavier sections.
Determine the needed amount of 8-foot or 4-foot sections. Add smaller or differently shaped platforms if necessary to fit design.
Calculate the materials list allowing 16 linear feet of 4-by-2 for every 4-foot section of stage, plus the combined length of all legs (4 per 4-foot section); 2 carriage bolts per leg.
Cut 4-by-2 lumber to make frames for each plywood section. Place two 8-foot lengths of 4-by-2 on the ground, narrow section downward. Use 4-foot lengths if making the smaller platforms. Place two 3-foot-8-inch lengths between them at either end to form rectangular frame. Drill pilot holes and screw frame together at corners using power drill.
Place plywood on top of frame, checking edge alignment. Screw plywood to frame with power screwdriver.
Repeat steps 2 and 3 for all sections. 8-by-4 platforms require additional support: flip over completed sections and fix two more 3-foot-8-inch 4-by-2's at 32-inch spacing, perpendicular to the longer sides. Drill and screw into these through frame. Flip platform over; screw plywood to supports.
Cut four legs of desired length for each platform (6 for 8-by-4 platforms). Fasten legs into each corner using two 6-inch bolts.
Drill 1/2-inch holes along the 4-inch deep frames at 18-inch intervals. Ensure these are in the same place on every platform for tying the platforms together; holes must align.
Fold legs inside the frame for transport and storage by loosening bolts.
Flip out and tighten legs. With two stage-hands per platform, flip platforms right side up. Place platforms tightly together in desired arrangement.
Fasten platform to platform by placing nylon ties through the holes in one platform into corresponding holes in the next. Tighten securely.
Check stability. On higher platforms place 2-inch wooden spacers between adjacent pairs of legs, drill through legs and spacer, fastening together with nylon ties.
Add the fabric "skirt" around the completed stage hiding legs.
To disassemble, remove the skirt, cut the nylon ties, and loosen and fold away legs.