Some content, particularly Python scripts must be installed to the Poser application folder for it to work correctly. With that said to install to a remote location you will need to perform the following steps:-

Create a new folder on your desired drive. Suggest not using the word "runtime" in the folder name. "My Extra Poser Stuff" good, "My 2nd Runtime" not so good. This because some Python scripts will search a file path for "runtime" and get confused if the path is "My 2nd Runtime/runtime".

Extract the downloaded content zip file to your new folder. This assumes that the zip has been created with the correct folder structure. Pretty much they all are.

In Poser go to the library panel and click the "+" Add Library icon.

Navigate to your new content folder, "My Extra Poser Stuff" in this example. Click the OK's

Your new library should now be accessible in the Library panel.

Hope that helps.