Summarize this article:

In the Internet, Setup, or Home menu of your router, check that your Internet IP address, DCHP, and DNS settings are all set. These should typically be set to automatic unless your service provider informs you otherwise. Many routers will provide a test button on the Internet menu page. Click it to check if your internet settings are configured correctly. This menu may be called Wireless, Wireless Settings, Basic Setup, or something similar. This page will display your wireless SSID, channel, encryption, and other settings. Find the field labeled SSID. This is the name of your network, and it will appear in the list of available networks for your wireless devices. Be sure to not put any personal information in your network name, as the name will be public. Make sure that the "Enable SSID Broadcast" box is checked. The Channel should be set to Auto. If you have a lot of wireless networks in your area, your router will automatically move the network to a clean channel. This can also be called the Security Options. Here you'll be able to choose which method you want to use to encrypt your network traffic. The options for most routers are WEP, WPA-PSK, and WPA2-PSK. WPA2 is the most secure mode of encryption, and you should use it if all of your devices support it. Only older devices do not support WPA2. The passphrase is what you enter when a device connects to your network. A strong passphrase will help protect your network from unwanted intruders. You should always have a passphrase for your network. Once you have chosen your SSID, encryption type, and passphrase, click the Apply or Save button to start your wireless network. Your router will process for a few seconds, and then your wireless network will be detectable by your wireless devices.

Summary:
Check your Internet settings. Open the Wireless settings. Name your network. Choose your wireless encryption. Choose a passphrase. Apply your settings.