Trying to use special characters in full page slider caption

Hi, I am trying to use special characters in full screen slider caption like this:
Next Pattern Design ►

There is a warning saying this might break the backend. Although the caption displays correctly on the page as this:
Next Pattern Design ►

I have downloaded the Avia Special Characters plugin but there seems to be no indication of how to use it. There is a small description here:
https://kriesi.at/documentation/enfold/intro-to-layout-builder/#using-special-characters < surely there are more special characters to list??

But I still don’t get what I am meant to change, nor how to use the plug in.
Sorry to be a pain, I see other posts have asked similar questions but these haven’t helped.

Thanks