What is the basic rule on how to make friends?

im moving to a new school and im not sure how to make friends... my sister told me they are all nice and funny... and dont give me the "BE YOURSELF" and "BE WARM AND FRIENDLY" . im very shy and thoughful . im very quiet in cl but when i do talk i make people laugh. but im not sure everyone has a sense of humor im scareed and nervous abut making new friends what should i do?