If you see Index of / message and list of your files and directories when visiting your website, it means there is no index file uploaded on your account.
Directory listing can be disabled from your control panel -> Folder Index Manager section -> select public_html folder -> choose No indexing
You can also upload an empty index.html or index.php file if you don't want any content to be displayed (but want to disable list of directories).
The best way to resolve this would be building a website! To find out the full guide on how to start your website on Hostinger, check out this article: https://www.hostinger.com/tutorials/website/how-to-use-hostinger-and-create-a-website