I am not a doctor, just a patient with some limited experience.
The marketing is really neatly done in the USA way of operating, so they promise you invisible solution, but really it is visible and better get over that.
Attachments will be added to your teeth, painless stuff, needs a bit of getting used to when you have your trays out, but you should not so… IPR or Interproximal reduction or mechanical removal of some of the tooth outer surface, oh now I got your attention. Needs to be done sometimes, to fit the teeth. It is not painful and you will notice the gap first tray after it then it will close up. Elastics for fixing the bite, annoying at first, then you get used to them and you can put them in in a second. Hook is priceless to put them on.
Ultrasonic cleaner and cheapest dental tabs (they want you to thing that only their expensive brand name is okay, bullshit). You will not want to brush the aligners three times a day. I clean them every morning in the cleaner with half of the tab. Hooks for taking aligners out and putting elastics in and chewies to get aligners to sit better. Portable toothbrush/pick, you will do a lot of brushing outside of your home. Water floss and electric toothbrush help.
Posterior open bite is real, don’t finish your treatment until your back teeth do not zip up and touch. Usually a few corrections are needed, think batches of multiple trays. Marathon not a sprint, whatever they promise. Painful only the second day after tray change. Wear them as much as you can. Elastics are a bitch to attach first week, then you go pro and do it in a minute with the hook. Nobody cares about your lisp, it will be there a day or two after tray change. Nobody cares if you wash your teeth in public restrooms. Nobody notices a thing, we are all self-centered and worried about our own insecurities. Don’t put trays in napkins or wherever, they will get lost or trashed. Keep them in the box case when mobile or UV cleaner when eating at home. Wait 15m after eating, then brush and put them back. I cycled extensively with trays in mouth, started using more gels, just be sure if you drink carbohydrates to keep a bidon of water at hand and rinse over it.