Open your Wireless Network Connection list and follow the steps below to select your device SSID:
For a Windows device:
1) Left-click Wireless Network Connection on the task bar.
2) Select the network name (SSID) of your router, click Connect and enter the WIFI key.
For MAC:
1) Click the AirPort icon.
2) Select the network name (SSID) of your router from the drop-down menu and enter the WIFI key.

Note: Available settings and menus may vary depending on device model and software version.