Router set up problems

I have a Linksys E 1200 Wireless-N Router I want to set up, so my grandaughter can use her Acer(Aspire One) notebook around the house. The modem  is a 2Wire with a Wireless Access Point cabled to it. First question: Is this particular modem considered to be a wireless modem or what? ( I was asked, and said that it was). Second question: How do I set up this router to this system. I tried setting up the router according to instructions from a sales person from Best Buy.... it didn't work . I cannot get on the internet the way I was told. Can anyone help me?