You can use a couple of Finder keyboard shortcuts to navigate your way through folders. It may not be much faster than using the mouse, but it can be useful if your mouse or trackpad isn’t working.
Finder Keyboard Shortcuts
You can use the arrow keys to highlight the folder you want. To move into the selected folder, press Command (⌘) + Down Arrow. To back out of that particular folder, just press Command (⌘) + Up Arrow.
Using Command (⌘) + Down on a file will open that file into its respective app, and the same command will open apps as well. It’s essentially the same as a double-click.