[ifelsethenend]

Favourites is no longer a required dependency (ie: it's optional) for Xonfluence on Matrix so the script is not enabled automatically.

You need to go to: Skin Settings > Scripts > Supported Addons and Scripts > Enable Favourites Script

If the script is also not yet installed (ie: a fresh install) you will immediately get the pop up dialog to prompt you to install it.

I just installed the skin and enabled the favorites script, but didn't get the pop up dialogue to prompt me to install it. So 'favorites' (star icon bottom left on home) still doesn't work. Disabled and re-enabled it and restarted but still nothing. 

How can I install that script now?

RPi4 with OSMC Kodi 19.1

Thank you.