Unable to set up wireless service to my router

Without additional info. Check some of the basics.

With you user manual or perhaps info found on your router log directly into your router thru your browser. If you can't find the IP for it anywhere on a label or in your literature try typing192.168.0.1 into your browser and hitting <enter>

Sometimes the default IP address is found on the router label if that doesn't get you to the login screen for the router. If you get to the login screen, your default User ID and password is often ADMIN, then ADMIN again. Once there you need to get into the wireless settings setup or find your SSID. (Your Wireless Network Name or technically your Service Set ID) Exampe: JohnsHouse Then you need to find or set your Pass key, sometimes called pin or password. Example 1234. These two things need to also match in the settings on any WiFi device you are attempting to add on to your network, such as a smart phone, tablet, or other WiFi device.
As with making any changes, write down the before and after settings of anything you change. Make sure to save when you are done. If a change doesn't work at least go back in and change things back to the state they were before you started. Additionally most routers have a reset that will change everything back to default factory settings. Doing that may change settings you have not written down. Those settings including the admin User Name and password. Everything will change to that factory default. The reset is usually found as a small hole that you depress a tiny button using the end of a paper clip or ball point pen. If you don't know what you are doing I don't advise resetting your router though. If you are still unsure I suggest contacting tech support for your specific router. They should be able to walk you through it on the phone.