How to survive the first day of high school?

Hi, my name is Emily and in early August I will be starting highschool. I only know about three people who will be going to the same school as me and am worried about making new friends. I tend to be more on the shy side but see highschool as a time for reinventing yourself since you are givin a clean slate. Any tips on how to put myself out there more without coming off as creepy? Also, any tips on just surviving the first day and the dreaded lunch break? Thanks for any feedback! :)