Have your wireless network name, or SSID, and wireless network key available. Both items are available through MyMidco by signing in and clicking on the Wireless Modem Network Key icon
From the desktop, click on the Airport icon, which looks like radio waves, in upper right corner
If it shows Airport Off, click on Turn Airport On to enable it
Airport section will show available wireless networks
Click on the wireless network name (SSID) you would like to join
Enter the wireless network key, or password, in the Password window
Click OK to confirm the password
Once connected, the Airport list will show a check mark next to the connected wireless network name. The Airport symbol in the upper right corner will indicate connection strength