Besides studying, you can make friends and do various activities at school.
At school, other than studying you can make friends and participate in many clubs.
Besides studying / other than studying= 勉強以外、
You can make friends = 友達を作れる
Various activities = 色々な活動
Participate in OO = OOに参加する
Clubs = クラブ、部活
学校の部活のことをよくafter school activites (放課後部活)かextracurricular activities(課外活動)とも言います！