Edit return home button

Hello

I have taken over a Storyline course from a previous employee and I haven't been able to figure out how to change the design of the return home button.

Every page has a home icon in the bottom left corner (this works to return to the homepage when in preview mode), however I can't select it and it isn't included in any of the timelines. I've had a read through the help questions and I haven't found anything like this.

Is this a special home button option I haven't come across yet? Or does my course have an error?

I look forward to hearing if anyone knows what's going on.

Cheers