changing homepage url

You can create a sub-directoy on your hosting and move the site into that folder, it can have any name you want. You will have to change the URL in the backend and then re-save menus and permalinks.

https://codex.www.ads-software.com/Moving_WordPress

So it can’t be done without creating a sub directory and moving the files? It’s impossible to achieve it with just editing some files and no moving of files at all?

That is how file paths work on all computers. a slash “/” indicates a folder/or directory.

So:

C:\WAMP\www\
and
https://siteUrl/images/nav/

Both are a path to a directory two folders deep from the root directory, C: or web root.