Inside a CRT

As you can see in the drawing, there's not a whole lot to a basic cathode ray tube.

There is a cathode and a pair (or more) of anodes. There is the phosphor-coated screen. There is a conductive coating inside the tube to soak up the electrons that pile up at the screen-end of the tube. However, in this diagram you can see no way to "steer" the beam -- the beam will always land in a tiny dot right in the center of the screen.

That's why, if you look inside any TV set, you will find that the tube is wrapped in coils of wires. On the next page, you'll get a good view of steering coils.