How would i access a backend webpage in a host?

I have uploaded a photo from my VS code editor as you can see below. These files then i have uploaded into my host provider "hostinger". Now usally the (index.html) page would be the root page of the webpage itself by accessing it like (SOMEPAGE.com). Also i have a (admin.html) file which is some sort of a settings page where want to be able to make changes into and access (index.html) page. The question is how would i be able to access that page the same way i would access the (index.html) or (SOMEPAGE.com) in the web inthe link bar of the browser? thank you for the help .