What specifically is not working? It helps to share some details on where a breakdown could be. Are you not getting Internet? Can you not reach the router's internal page when you connect up your modem? How is each device connected (as far as AP <> Router is concerned)?
Make sure you're connecting from one of the 4 Actiontec LAN ports. Do not use the Actiontec WAN port.
On the Linksys WAN settings page, is it set to "Obtain DHCP address automatically"?
What is the LAN subnet of the Linksys? It must be different from the Actiontec's LAN subnet. i.e. the Linksys LAN subnet can NOT be 192.168.1.x.