Click the Apple menu then go to System Preferences.
When the System Preferences screen appears, please go to the Internet &Wireless section and choose Network.
On the Network screen, please select Airport/WI-FI, and then click Advanced.
Under the Airport tab, click the button “+”.
A windowwillpop up, please type the network name->select the security type->input the password->Click Add->click OK.
Or you can click show Networks to search for the network->select the network and type the password->click Add.