How do focal length, angular magnification and field of view relate? The larger the focal length the larger the angular magnification The smaller the focal length the larger the field of view.

I don't understand why this applies. I'm talking specifically about telescopes.

Wouldn't a greater angular magnification imply a greater field of view too?
Magnification and Field of View are directly opposite. A low magnification will give a large field of view, and a high magnification will give a small field of view. (Field of view indicates how "wide" is the portion of sky that is viewable in the eyepiece.)

Think of looking at the Moon with low power. Let's say the Moon fills 1/4 of the view, meaning that you could get 4 Moons lined-up side by side across the view. When you increase the magnification, the Moon looks bigger, so it fills more of the field of view. And therefore, you can get fewer Moons lined-up side by side. If you double the magnification, the Moon fills 1/2 of the view, meaning you can now only get 2 Moons side-by-side in the view.

Note that the above example is unusual for a telescope, depending on the design of course. Most astronomical telescopes used by amateurs will show an area of sky slightly larger than the Moon when using "low" power. Being able to fit 4 Moons is a bit of an exaggeration, for easy of explanation.