How to make the index file visible so I can see layout to edit?

I recently hired someone to create a WordPress CMS for a one page website. However, I have no visual representation of the page to see the layout and what I am editing… Any suggestions would be helpful. I have the index code, I see that they have placed this in two different locations (front-page.php and header.php) but it is not available on dashboard under “pages”. This is where I need it so that I can toggle views between Visual and HTML.

Thank you in advance!!