A couple of these links were included on another forum that I monitor.
This a short towing guide that has some good information, but 1 section I can't quite decipher. It also includes the trailer length/tow vehicle chart that is sometimes used on this site.
These 3 links provide some detailed explainations on many towing terms, hitches, weight ratings, and such.
This used to be the old standby, but I think the Toyota links do a better job with the basics......and I am a Ford guy.
The 1st part is about their products and ratings, but near the end of the pdf they get down to basics.....but still not in detail like the Toyota pdfs.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263