Put on the goggles and the respirator mask.
Measure the height and width of your walls to determine the sizes of foam insulation you will need. Because you will glue the insulation into place, you do not need to initially worry about studs in your wall. If you cannot adequately glue the insulation to the wall or later decide to cover the insulation with wood, you will need to employ a stud finder.
Mark the required measurements on the sheets of insulation using a piece of chalk. In most cases, you will just have to trim the sheets of insulation so they will fit, closely placed, on the wall. In some cases, you may have to place smaller pieces of insulation around fixtures, such as air vents, ducts or architectural details.
Score the sheets of extruded foam insulation along the chalk marks using the utility knife; snap the insulation along the scored lines.
Spread the foam adhesive on the wall. Use the brush as necessary to ensure an even, but generous, application.
Press the insulation sheets against the foam adhesion to glue it into place. If you have trouble getting a good seal between the foam and the walls, you can drill holes using a hammer drill with a masonry bit to install sleeve anchors and screw the insulation to the wall. In this case, use a stud finder to locate studs in the walls.
Caulk any seams and gaps between pieced together insulation around fixtures. This will help block air leaks. Allow caulk to dry according to the manufacturer's instructions.