how can I access a PDF directly from my home screen

Mark it as "Starred" (click the little star icon next to it) and then you'll always be able to access it directly via the Starred section of the home screen (just under Recent at the top left).

@Stan288267538z8j 

The Home Tab in Adobe Acrobat Reader shows a list of your recently opened files. If you open and close a PDF, it will then be listed on the Home Tab.

Jane