Cut three of the 2x4 studs to 6 feet in length using a circular saw.
Cut the 7/16 sheet of OSB into strips 16 inches wide. Each strip will measure 16 inches by 8 feet long.
Locate the studs in your wall using a stud finder. Mark the location of each one with a pencil.
Measure from the floor 2 feet. Mark this distance with a pencil the entire 8-foot length where the shelves will go.
Measure up from the floor 4 feet. Again, mark this distance with a pencil the entire 8-foot length where the shelves will go.
Measure up, from the floor 6 feet. One last time, mark this distance with a pencil the entire 8-foot length where the shelves will go.
Locate your 2-foot pencil line on the wall. Place an uncut 2x4 flat on the wall so that the pencil mark is in line with the top of the 2x4. Install one 2 1/2 inch screw through the 2x4 into every stud in the wall (which you located in step 3 of the first section).
Place another uncut 2x4 on top of the previous 2x4 installed. Hold it in place by installing two 2 1/2 inch temporary holding screws only part way in. Do not screw them in all the way.
Continue this same procedure with 2x4s at the 4-foot mark and 6 foot mark.
Place the two of the three 6-foot 2x4s on each end and the third in the middle. Secure each of these with two 2 1/2 inch screws on the points they intersect with the previously installed 2x4s.
Remove the 2 1/2 inch temporary holding screws. The outside bracing is now free to move. Pull it away from the studs that have been secured to the wall and place the cut pieces of OSB on each shelf level. Secure the OSB with 1 1/4 inch screws into the 2x4 bracing.