I have managed to input all the data to position the 2x3 individual stickers on the A4 sheet to perfection. Sadly, I am trying to print round stickers and the template thinks I mean square. Help! How do I explain to Microsoft Word that I want round ones?

Does this label have a number?
Look under the Options button in the Labels dialog.

Note that labels in Word are Tables and rectangular. You could include Wordart in your labels to shape the text, this will be labor intensive.