I need a point in the right direction.

The site is currently disabled to visitors so it shows that login page that appears.

I'm using a theme called Minimalist and would like to manually edit that homepage but I'm not sure what file it is. I've spent sometime looking for it but I cant find it so does any of you know where I should be looking?

I dont want one of those homepage plugins and I dont just want to edit the text via the edit language section of admin panel.