Clean the walls with a power washer. The adhesive for the insulation boards will hold better to a clean wall.
Cut the pink foam boards to fit the walls by placing a straightedge along the cut line and creating a score line with a utility knife. Snap the board at the score line.
Apply Styrofoam adhesive to the back of the first pink board.
Install the board in the corner of the first wall. Stand the board up vertically and press it firmly against the wall.
Install the pink insulation boards along the bottom of the walls, repeating this process until the bottom edges are covered.
Measure and cut boards to fit a second row, if necessary. The board in the second row will be installed horizontally.
Install the boards in the second row by applying the Styrofoam adhesive to the back and pressing them firmly against the walls. Stagger the boards in the second row so the joints between the boards do not line up with the joints between the boards in the first row.
Place installation tape over the seams between the boards.