RenderMan for Houdini (RfH) is an integrated interface to RenderMan inside Houdini. RenderMan 24.0 features are now available in Houdini 17.5, 18.0, and Houdini 18.5.
RenderMan for Houdini requires the installation of RenderMan Pro Server as well as the RfH plugin in order to function correctly. The RenderMan installer does this automatically.
To complete the setup you should follow the directions for Installation of RenderMan for Houdini.