Cork backer usually comes in rolls of 2'x4' and tiles of 1'x1'. If using a rolled cork, unroll it and cover it with a flat object in advance to allow the material to relax. Next, thoroughly shake a can of spray adhesive for at least 60 seconds.
Spray overlapping rows of adhesive on the piece of sheathing. Make sure to evenly cover the surface and be careful not to overspray onto surroundings. Start at one end and evenly roll cork across the sheathing. Work slowly to prevent bubbles in the surface. Overhang on the sheathing will be trimmed off later.
Next staple the perimeter of the cork to secure. Make sure the staples are within 1/2” of the edge of the board. Flip the sheathing over (cork side down) and trim the excess with a utility knife.