How do i Drain the fluid? Where is the Drain plug located at?

If you are needing to drain the entire P/S system then the first answer is right on. If you just want to change the fluid (not a bad idea on this older truck....so go synthetic) you can get a squeeze bulb at any auto supply. I've used them for this purpose and others...even an anti-freeze tester can do the trick in a pinch. A squeeze bulb will get most of the P/S fluid out of the reservoir, draw down an overfilled battery (or brake fluid reservoir too) and it's cheap.

1st or foremost why would you want to drain this and second of all to drain a power steering pump you must take the line off the back of the pump . Most of the time you dont need to drain this unless u are taking the pump off and that is the only way