I think my answer will help both. As far as I know:
1. Only files that can utilise the Free Kontakt Player without the 15 minute timeout (ie a licence fee was paid by the originator of the library to NI)
can use the Library Section. That said check out on YouTube as I believe there are some workarounds so it is possible but see 2 below first.
2. To access quickly I load my Pianobook Instruments in Quickload (CTRL+F) and find that is fine.