After you have gathered all your materials together and cut them to size, you will need to bring those pieces together so they can fit properly. They have to join together and be kept together so there can be a sealed corner on each side. The way to join all pieces together is by using either glue or some other type of adhesive to make the joint stick. After you have applied the glue or adhesive, you need to use a good metal strap clamp to hold the clamps together. It is best to use a metal strap clamp because you can see all the four corners of the frame at the same time. This way you will know if all four corners are connected correctly before going too far. This way if a mistake occurred you can fix the problem before the adhesive hardens.
There’s one thing to be watchful for here regarding clamping. When you place the adhesive over the joint and place the clamp over the joint, you don’t want to squeeze the clamp too much or you may have a crack on the joint. You do need to place the clamp and tighten so as to form a good clamp, but don’t overdue it. Just tighten it until you find tighten is hard to do. Then stop. When this happens, it creates a weakness, thereby causing a separation later. So be careful when clamping the corners. This is why using a strap clamp is a benefit, because it makes clamping easier and more accurate. You don’t have to judge as much. As long as all corners match up evenly then you should be in great shape. Just make sure you used enough wood glue. This will add extra holding strength.