How to add a custom design to Apache Files Directory

I recently created an instance on GCloud and installed Apache and added a 150 GB Hard Disk. I want to use it to store my files.

I have a question, can I customize the look of the Apache directory listing. I really want to do it. The default one is not so user friendly.

Additional question, can I add additional disks to a running instance?

Put this file on PHP server, done.

Done. Thanks.

What about the second question?