Be yourself. BE YOURSELF and you will be fine.
If you are an athlete, see if you can find the info for the coaches, online.
If you want to try a sport, or club, ask. (We had a pizza club whose primary focus was to order or make pizza, for lunch, twice a month and rate the temperatures, mixed toppings, speed of delivery, etc.) Once a month they went to local pizza places and shadowed the work teams and helped out by making boxes, cleaning, learning about the ovens, noting how supplies were ordered, etc. The sponsoring teacher’s family owned a pizza place back East; he loved pizza, so it was an approved club.
(We used to have a Procrastinators Club but no one knows who is in it or if it still exists because no one has shown up. They never asked for a teacher advisor.)
We had 28 athletic teams at our high school and it’s one of the best ways to acclimate to the school. The school had an assembly during the first month of school, to promote the teams, with representatives from each of the teams. They handed out Athletic packets with required forms for physicians’ approvals, parent permissions, health concerns etc.
At our local high school in Southern California, they assign an upperclassman to be a buddy for the week (or more if the new student desires it). They are part of the “Link Crews” and have to be interviewed by the staff. They are generally well-liked by teachers and students, are down-to-earth, kind, and are chosen because of their good communication skills. These kids have to be selected. There is a wait-list for these positions.
The Link Crew member has been “trained” to guide the “newcomers” to the school and answer questions about the school, teams, social groups, ID cards, off campus and parking passes, and introduce you to students in your grade. They eat lunch with the new student for the week and Uber-in some foods for lunch.
Students in your grade level sign up to eat lunch with you and your Link Buddy because the Brown Bag, Uber eats, and Jamba Juice/Starbucks Frappuccino’s are very good lunches. (There are three local Starbucks very close to the school -if that’s your thing.)
I know that our local HS is unique because it has a plethora of cultures, so they try really hard to assimilate students to school/ student life.