If I follow the link in the Package Manager it leads to a GitHub page where it says: “The command DenoiseRaytracedCheck will walk you through the setup of the tool.” Sounds promising!
But if I do so in Rhino, a Windows Explorer opens and a zip file downloads. Not what I would call a “walk through” but I understand that I have to copy the content of the zip archive in this opened folder.
After doing so, the command DenoiseRaytraced asks for a file name and location, a width and an height, the number of passes and the it aborts saying it wasn’t able to start the Raytrace mode.
Ok, I found the problem; the viewport must not be in Raytraced mode before entering the command… it may be worth it to check for this?