Mark O’Brien has written a generic instruction manual for using old folding cameras. Contains heaps of example pictures and should be enough to get you started.
Folding cameras are usually quite reasonably priced, are easy to carry, generally have good optics, and can provide an inexpensive way into medium format. While this PDF tells you how to use them, certo6.com has a good feature/shooting experience overview for many of the more common folders.