I'm confused about all the various things that seem to go with changing + change pads and need some help!

I am going to get something like this to put on top of a dresser http://www.amazon.ca/dp/B00O64QJOC

It seems there are also then sheets like this to cover it
http://www.amazon.ca/dp/B0118X05QQ

And these change pads
http://www.amazon.ca/dp/B0118WZOLI

And liners!
http://www.amazon.ca/dp/B009UPUJIY

How do you use all these things together? And which do you actually need/did you use for your changes? I'm assuming those individual changing pads are useful for throwing on the floor/couch/wherever, so those seem practical. Do I just throw those on top of the dresser pad and that's it, or do I need the sheet and disposable liners too?