Setting up a PPPoE connection between router & modem

Hello, I think I'm experiencing a NAT networking problem, as most games I play complain that my NAT is moderate, or sometimes strict. I've researched this and found out it may be a Double NAT problem.

I've also researched two solutions for this: Disable NAT and DCHP on either the modem or router, or set up a PPPoE connection between the two. Can someone tell me which one is the easiest to do and how to do it?

Router: Linksys E3200 w/ Cisco

Modem: Motorola SB5102

Other Info: This IS a broadband connection, and I believe it is a DSL or Cable setup. I also know how to access the router settings, and how to disable NAT and DCHP. However, I do not know how to connect to the modem (I do know the default IP for it) and don't know how to perform a PPPoE connection, as this would be my first time.

PPPoE is for DSL connections... Go to the router and modem websites and download the instructions from there. It will explain how to connect and access the router