Slide one side rail into the grooves of the headboard. Make sure the platform for slat attachment is o facing the inside of the bed. Repeat this process with the other side rail. Next do the same with the other end of the side rails into the foot board. Then tap the top of the rail ends gently with a rubber mallet to make sure the connections are secure. Full / Queen Spread the slat bundle cloth side down evenly across the slat rails. First secure one slat on one end and then the other end evenly.