Button in Access to open specific PDF file

Help with Access 2010 and Adobe X
I’m trying to create a button on an Access form, that when clicked opens a specific Adobe file based on information in a text box. The form displays only one record at a time. The field contains only a purhcase order number such as 150368. The Adobe file of this purchase order is named 150368.pdf.

Form name: POinquiryFrm
Based on table: POinfoTbl
Field name: PONumber
Location of Adobe files: L:\Facilities\Financials\Purchase Orders\ ******.PDF

Thanks for the help,
Jeff