Authenticity of Scanned PDF?

Hello,

I’m new to digital forensics, but needing to determine if a multi-page PDF document contains elements that were manipulated from the original documents it contains. The metadata reflects the fact that the PDF is comprised of multiple scanned documents, so the original metadata associated with each original document has been lost. Is there a way for someone who doesn’t know much about digital forensics to determine the authenticity of the documents within the scanned PDF?

Thank you!