How do I connect my emachine to my wireless internet?

[Trailmix1]

I am trying to connect my mother's emachine to our family's AT&T wireless internet. It will not find the wireless signal. In troubleshooting the problem, it tells me to connect to a local area connection. How do I fix this?

 

[popatim]

Emachines dont normally come with a wireless adapter. did you install one?