First, read the English article below.

It's in the upper-right corner of the Mac's screen. If you see here, click it, then click Turn Wi-Fi On. It's the name with a ✓ to the left of it. The name you see here is your network's current SSID. Any network names you see here are the SSIDs of other networks near you. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Nhấp vào ứng dụng nằm ở góc trên, bên phải màn hình. Nhìn vào tên mạng. Xem qua các SSID có sẵn khác.