If you already have Archicad running when you copy the new library parts to your library folder then you will need to "Re-load" the library in the Library Manager.
Otherwise re-starting Archicad and ensuring the correct library folder is loaded should do the trick.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11