here, the video says that she's a "master artist" and I'm only an amateur artist so go and watch the video if you want some expert advice on canvas stretching.
Here I've provided for you some photos of my second attempt at canvas stretching (the first one went well too but I didn't take any photos). It really is as easy as it looks, hopefully my amateur attempts will encourage you to have a go. The woman in the video says something about using extra equipment when stretching large canvases, but this one was quite large and I didn't have a problem with it not being taut. I pulled the canvas as tight as I could while stapling and this seems to have been enough.
First you start with one side with one staple, then do the opposite side, pulling the canvas tight. Then one staple in each of the remaining two sides. Then you put two more staples on each side of the first set of staples , a few inches from the first ones. The next step is to pull the corners tight, fold them and staple them down. You have to do this stage now because when all the other staples are in place it will be impossible to stretch the corners properly. Finally you go round putting in the rest of the staples.
Apparently this way of stretching a canvas is called a gallery wrap because you only staple it on the back, I'm not sure why they sometimes put staples along the edge too, they are a real hassle to get out again. I'm not sure of the best way to take staples out of pine but the little staple extractors for paper just won't hack it (unless you have an incredible hulk grip). I use a cheap screwdriver and mallet to dig staples out, sometimes I take quite a lot of wood out of the frame too, there must be a better way. Also with the modern extra deep canvases you see everywhere now you wouldn't want to put staples down the edge.