It's simple. If you have the address of BBS, please log in directly. If not, please follow the following steps. For example, if you want to enter Peking University, use Baidu: Peking University BBS→ After entering the page, if you are a tourist, please click Visitor (BBS in some schools may not be open to tourists). For example, if you are not a tourist, you can log in directly: enter your login name and password (if not, you can register), but it will take some time to register.

good luck