To create a double mat, select two different colors of mat board. Use the mat intended to be the liner or second mat, and use a straight cutter to slightly downsize it. It is important that the liner mat is slightly smaller than the top mat. Now select a border size and set the mat guide accordingly. Mark borders on the top mat. Always insert a slip sheet before bevel cutting. Now insert the top mat into the machine and cut all four sides. After the fourth cut is made, lay the top mat face down on the table top with your window still in place. Now using a backless tape such as ATG tape, apply adhesive to the back of the top mat. Be careful not to let the adhesive get too close to the cuts. Make sure that the adhesive is also placed in the center of the dropout window. With the window still in place, lay the liner mat color side down onto the back of the top mat so that the adhesive connects. Now reset the mat guide slightly larger than the previous border. Quarter inch is standard. Place the entire mat back into the machine, then mark and cut all four sides. After the fourth cut is completed, the two windows which are stuck together will fall out and you will have a perfectly aligned double mat. You