Once imported, the library should appear in your list. You may need to check a box to it or double-click it to set it as the current active library.
There are active polyboard user groups. Search for "Polyboard Users" on Facebook. These groups often have a "Files" section where veteran users upload their quick design collections. – always scan downloaded .plb or .zip files for viruses. polyboard quick design libraries download
Assuming you have found a .blb or .spb file for quick design, follow this installation guide to ensure it appears in your menu. Once imported, the library should appear in your list