Zotero has a limited amount storage space, which goes fast when you're saving PDFs and eBooks! Don't worry, it's easy to link to full text using the web, Google Scholar, or WKU Libraries from within Zotero.
To link to full text from WKU Libraries, you'll need to configure your preferences:(Edit then Settings)
Under "General," go to the base URL line and paste the link below:
https://saalck-wku.primo.exlibrisgroup.com/openurl/01SAA_WESTKY/01SAA_WESTKY:WESTKY?
Now close the window to return to Zotero.