If they are quadrature encoders, you'll need at least 2 inputs, Count A and Count B, so say X0 and X1 for the first encoder. The remaining X2 input does something else, and may or may not be needed for your application.
You can find the value in the $DeviceName.Acc (or ScaledValue, etc) in a Data View to get a feel for how the numbers look before you massage them with MATH, etc.