The Optical Amplifier is a simpler model and doesn’t have a relation between wavelength and gain. I would simply use it first to make sure the simulation is running successfully. You can change the noise power with the noise figure option or completely disregard the noise by unchecking Include Noise.
Once your simulation is working with this simple model, try using a more advanced model like the EDFA component or the Optical Fiber Amplifier. These include options for a wavelength dependent noise/gain distribution.
Regards