Stretcher Bars- wooden slats that are made to fit together. Each stretcher bar is one side of the canvas. Premade stretcher bars are available or you can make your own. Brass upholstery tacks were commonly used because they do not corrode.
Staples are easy to put in place and easy to remove later.
Strong material is needed because the fabric is under great tension. Slide mitred edges of four stretcher bars together. Make sure that you have two of each size stretcher bar. Check square by measuring corner to corner, then repeat for the other two corners. Adjust frame until both measurements are the same distance.