If you can't find any good, local training options you can at least watch free Youtube tutorials. Watch several on the same topic and you will get the gist of the job. Then try it out yourself, with the videos on hand to refer back to as you go.
If you have never changed a tire you should make it a point to do so. Particularly to do so at home, in a safe place, on level ground. In the real world you may be doing it at the side of a highway, on a sloped shoulder in the mud. Make sure you are comfortable with the basics of the job so you can pay more attention to your safety and your environment when the time comes.
A flat tire is one of the most common of all vehicle failure modes, regardless of make/model/year. And if you plan on going off road then you increase your odds courtesy of the ground you travel (i.e. not smooth).
Get to know your jack points.
There are torque multipliers for those who lack the strength to break the lug nuts loose. It can be as simple as a long breaker bar, or you can get a gear driven torque multiplier. Or carry an impact I suppose. However, I am not impressed with impacts in general. I can break the lugs on my dually far easier/quicker by hand than I can with my Milwaukee M18 Fuel impact. And that is supposed to be a good one. My Ingersoll Rand air impact is no better.
Once you have mastered changing a tire then get to know your battery and how to jump start your vehicle. That is probably the next most common failure mode. Learn where the battery is (not as simple as one would hope on some vehicles) and how to tell the positive from the negative. Learn how to hook up jumper cables. Figure out if you are capable of changing your own battery (being full of lead they tend on the heavy side). At the very least make sure you know how to refresh and maintain your battery connections (and be careful of battery acid--it is serious stuff). Make sure you at least have the right tools to disconnect the battery and its hold downs.
Those are the two most general skills to make sure you have. After that you need to get more vehicle specific. You will have to find out what problems are most common for the platform you drive. For my Jeep Cherokee it is the crankshaft position sensor that is most likely to be a surprise failure. You will have to do some research to find out what goes out most frequently on your vehicle. If nothing else, ask your mechanic. I am sure they will have a sense of what goes wrong with those vehicles.
One other way to learn is to go to a pick-your-part junkyard. Just looking at half disassembled vehicles will give you a sense of what is going on underneath the skin. Take your tools in and start disassembling things. You will learn about the various fasteners (some things are like a puzzle) and about your own limits. And there you can do so without endangering your ability to get to work on Monday.
If you are intent on learning there are plenty of ways to get there without a formal class. I have no formal automotive education, but the only part of a car I am not comfortable tearing into is an automatic transmission. I have rebuilt my own gear boxes and differentials. I have rebuilt my own engines. I have even done several frame replacements. None of it is rocket science. Attention to detail will cover most all of it.
