hmm.. after thinking about it, i see this is sorta like describing how to tie a shoelace.. If there is someone who can show you , you'll see how simple changing a tire is.
Not to say it's always easy. Sometimes it takes some strength to leverage the tire irons, and get that last bit of tire over the rim. It depends on how your tires fit your rims. I have a set of short plastic bicycle-type tire "irons" and they work on this moped because the fit is loose compared to other bikes..
99% of good technique is to take care that you don't pinch an inner tube and end up with a flat tire. Careful placement of the iron as you work your way , little by little, around the rim is whats needed.
A bit of soapy water is helpful to reduce friction but the soap remains there and it's slippery.. Friction is the only thing stopping the tire from spinning around the rim, tearing the valve stem right off the innertube like during an emergency braking situation.
Professional tire changers use something called 'tire mounting fluid". After this stuff dries it is very tacky and theres no danger of spinning a tire. I prefer to use nothing at all for lubrication on these little tires.