First of all, I really don't know where to sign up for this summer school.

Generally, you can enter from the east gate and the west gate because it is close to the subway station.

Tsinghua is very big ... Walking around is very tiring. I recommend you to take the school bus near the west gate.

Generally, the possible check-in place is Bauhinia Apartment or Building C (this is the previous check-in place, not necessarily allowed). There is still a small term in Tsinghua, so someone is taking classes. Just ask the students near Bauhinia apartment.