Measure the area where the stage will be constructed. If the stage will be in a hall, on the street or in another venue, it will have unique size constraints. Get a good idea of what the environment in which the stage will be located is like.
Talk to the magician. Determine what, if any, special requirements he has for the stage. If the magician has special requirements, take detailed notes of them. The magician will likely have constructed stages before based on the specifications.
Construct a support frame. Determine the height of the stage first. Assemble four 2-by-4s with a length of 4 feet in a square shape on the floor. Use heavy-duty nuts and bolts to assemble the square together. In the four corners of the square, attach 2-by-4-foot posts that are the desired height of the stage. Assemble another 4-by-4-foot square like the first one and attach it to the top of the posts, creating a three-dimensional frame of a square.
Attach a sheet of 4-by-4-foot plywood to the top of square frame using screws. Make sure the plywood is strong enough to support; a 1-inch-thick square will be strong enough.
Repeat Steps 3 and 4 to construct additional frames. Make as many other frames as necessary. Place the frames next to each other and attach them with bolts through the 2-by-4s underneath.