Cross over, straight thru, roll over

I am a ccna and I can’t get a staraight answer on when to use the above cables. I want to take 4 PCs connected to a hub. Connect the hub to a 2500 series router and on the so port connect a PC. I want to do this to set up a basic lab to play with two networks connected via a router. What type of cables do I need and how do you define the above cables?