This PDF file is an overview of stretching you own canvas.
Stretching your own canvas requires a lot of gripping. If you are planning to stretch many canvases you will need a pneumatic stapler and good tools. This PDF presumes you are stretching a large canvas that would need bracing in the back. Smaller canvases, under 24" x 24" will not need bracing.
Avoid placing your bracing down the vertical center of the canvas, which would interfere with hanging hardware.