Live Feed on Amazon CBS Channel Question

So I got the live feeds through my Prime Amazon account. Bought the CBS channel app. I cannot find a playback option to go to timestamps. I got the live feeds on Amazon so I wouldn't have to d/l anything on computer. But it looks like I can only see what is live now and not able to go back. is this true? If I cancel from Amazon and get directly from CBS, will I have to d/l a player? TIA