Locate two studs behind the wall in the garage, using a stud finder. Find two studs spaced the same distance apart as the length of the bin rails. Standard rail lengths that fit within standard stud distances are available. Mark the stud centers at several points with a pencil.
Place the first post vertically, centered on the axis of the first stud. Place a level along the side of the post and adjust it until the level indicates that the post is plumb, or straight up and down vertically.
Screw the posts to the wall. Use the supplied screws, and drive them through the screw holes in the posts and into the studs behind the wall.
Measure the height of the first post. Set the second post against the wall at the next marked stud. Place the top of the post at the same height as the first post. Plumb the post with the level and screw it to the wall.
Position the first rail at the desired height. Hold the rail horizontally with the upper hooks facing up and toward the rail. Insert the upper hooks into corresponding slots on the posts. Once the upper hooks are engaged, slip the lower hooks into the slots below. Push down on the rail to engage it in the posts. Hang additional rails above or below in the same manner.
Set the back lips of the plastic storage containers over the protruding upper edges of the rails. Allow the containers to hang naturally, with their backsides supported by the wall.