So confused on what Routers and modules in Packet Tracer to use with Todd Lammle CCENT book. I'm looking at Figure 8.8 on page 345 and it says I need serial port S0/0 and S0/1 on one of the routers. I can't find the routers or modules that have these ports. I'm stuck here and not sure if I'm even asking the right questions! Please help! Also, is there another easier way to learn this?