Adding a new language

Hi I have the pro version and asked you this question via your online form a few weeks ago but haven’t had a reply. I’d like to make a french and english home page – but the customizer only seems to allow one language. However this theme says it’s translation ready.

Is there something I still have to do to get a french ‘customizer’ for the home page – and other pages?

I’m using polylang plugin if that helps.