How do I survive in high school?(fresh meat)?

I don't i'll get beat lik that im talking about other stuff like dealing wit teachers,studnets,princpals,grades,lunch… already have of frens to cruz wit)im mean by lunch lik what do, extra credit. And for grades i keep a 3.5 GPA in 8th grade how u think i can keep it. I actually not that smart lik how ppl think,