You needn't move or drag-and-drop anything. You can leave all your content in the P4 runtime, and access it from Poser's library panel. This is known as "multiple runtimes", and it's one of the wonderful new file-management features you'll soon enjoy.

I only have the Windows version of Poser, but if the manuals are similar, you should find the information you need in Chapter 15: The Poser Library, under "Adding Libraries".

geep has an illustrated tutorial on the subject around here somewhere, and jelisa also describes the process at Fignations.