Download a PDF such as a Dymo Label from PS Online and click the arrow next to it and then "Always open with system viewer"

Open the settings app

Select the label printer

Select “Manage”

Select “Printing preferences”

Select “Advanced” in the bottom right on that popup box

Change the paper size to “11354 Multi Purpose”

Click “Ok”, “Apply” and then “Ok”

Open Adobe Acrobat Pro (Or any PDF will open Acrobat) and click print

Set “Page Scaling” to None

Untick “Auto-Rotate and Center”

Click “Ok” in the bottom right to save these setting (It may print that example PDF you just opened)