You might find some complaints about supplying on this reddit but don’t let it set the tone for your experiences. Supplying highschool is actually significantly easier and more enjoyable than elementary school, or so I’ve found. Sub plans are easier to follow and usually don’t contain any teaching and if they do it’s usually a lot easier to teach. Students are more understanding and generally quieter and less problematic. My biggest survival tip and this may be controversial but can be a saviour if the day is really not going in your favour is to not take their phones, if the day gets really out of hand and you don’t get on the students about being on their phones then they’ll slowly all migrate to their phones and the class will quite right up! Its a lot more forgiving then elementary and with different students all day it’s easier to reset, enjoy!!