add link on portal page in Dynamics 365 to download a file from OneDrive

Hi,

I am trying to add a link on the Portal page to download a file from OneDrive, 

I have a default report template in OneDrive. When a user clicks on a button or link on the Portal page, it runs a flow to populate data in the report template, save it as currentDate_siteLocation.xlsx and download the report for the portal user. 

I tried to open the file from OneDrive. A link for the file includes sourcedoc parameter with a different value each time when a new file is created. therefore, I won't be able to hard code the URL  as "URL for OneDrive + "filename"

Any suggestion on how this can be done?

Thank you,

Siva