CRP-5 = E6B = whizz-wheel = flight computer = Dalton Computer.
They are all basically the same thing, and not the same as an Electronic Flight Bag, although EFBs will generally also include the functionality somewhere.
And as already mentioned there are loads of YouTube videos and online guides. It isn't complicated, just a bit alien to people too young to have ever used a slide rule - which let's face it, is most people nowadays.
G