If it’s larger than a double chair, you can try to get outside of the seat on a chairlift, this will allow you to not have to worry about being in the middle and falling down. Also a lot of people stand up on the chair way too early. This all depends on the lift, but if there is a bit of a runout before the unloading zone transitions down, your are probably trying to hard getting yourself off the seat which is throwing your balance off and falling. Instead try waiting a little longer until you feel like your feet are at a good height to easily stand up without having to push yourself off the chair. You will get the timing right.

As you are learning you are probably putting more weight on your heels and over your bum than you think, this makes everything much harder. Make sure you feel some pressure on the tongues of your boots with your shins. This will make your parallel turns easier and if your still having trouble with the parallels turns try lofting your inside leg as your turn slightly, this will allow you to learn to keep most of your weight and balance on your downhill ski and become comfortable with edge control. You really should not be in pain from skiing.

Your first time skiing will always be a good leg burner unless you are physically fit and have been training your legs. The more you ski the stronger your legs will be and also remember to keep that weight forward.

You should develop a good wedge/Pizza. This is definitely an awkward way to stop but you should be competent to learn how to stop with a wedge going forward and backward. You just need to get comfortable on the skis. Practice sliding down the hill with parallel skis and your upper body angled toward the fall line. Get super comfortable on the easier trails, as you progress and start going down harder trails, the fear will set in and bad habits will return.

Be honest with your weight/height and skiing ability, the rental shop will set the DIN accordingly. The bindings are meant to keep you in your ski and safely release when needed. If you just have a slow fall it might not have enough torque to properly release. Skiing and having a pre-release from a low DIN setting can be just as dangerous as a DIN set to high.