Hi dshield
Welcome 
The V4/M4 Elite products, are designed to be installed into a “Runtime” folder structure, so if you have Poser or DS, you can install the elite Morphs and textures into either the Poser, or DS.
In DS, the Elite products will only show up in the “Content Library” since they’re not “Smart Content”.
There are separate “Elite” Carrara shader products available in the store, as the main Elite products only shipped with Poser and DS shaders.
In Carrara, you can create your own Elite shaders by manually loading in the Elite texture maps you want to work with, in the shader room.
Once you’re happy, you can save the shader as a “global shader” like a (preset) in your My Shaders section of the Browser.
The Shaders you have from HollyForest, are a slightly different issue..
In Carrara, you may need to either add the folder which contains the shaders, or refresh the browser, so it can find them.
It depends on where you installed them.
They should be installed into your main Carrara program folder.
Hope it helps 