Some resources I've found helpful over the years:
In my opinion, U-Haul's "Safe Towing Guide" is an excellent resource that explains the basics very well.
Link to guide E-trailer has a good page explaining the different "classes" of hitches
at this link and another about weight distributing systems and add-on sway control devices
at this link.
Finally, Changing Gears has a calculator that can help one to determine real-world compatibility of a tug/trailer combination. Access by going to/reading the info at their "tow vehicle sizing" page
here.
Links to the calculator are provided at page bottom.