Make sure you have the latest version of the Neural Amp Modeler (NAM) plugin installed.
You will receive a .nam file.
If the profile is labeled as a full rig profile, you only need your .nam file.
If the profile is not labeled as a full rig profile, then you will need to load an Impulse Response (IR) audio file, alongside your .nam file.
Select the button(s) indicated in the previous image to load the necessary files.