Stage Play UK Format - Dual Dialogue Help

Hello, I’m having an issue getting the dual dialogue to work in the Stage Play UK Format.
I have already had a search in the forum and followed the advice but when compiling it doesn’t work.
So far I tried selecting the two bits of dialogue I want to be simultaneous and selecting ‘preserve formatting’, then when compiling I would go into ‘text layout’ and make sure the box was ticked next to ‘convert preserve formatting blocks to dual dialogue tabs’ but nothing changes when I click compile…
Any suggestions?