This means that you can try by your own to CHMOD the web folder and even the html file (I would suggest to try with the file for the first try as root created it I guess).
Sorex is right about 775
Please don't stress. It is usual to be lost with such problems when starting. After that it will just been fine.
When you talked about a Webadmin application, is it Webmin ?
Yes, Webmin menu at its top : "Action logs" and you'll find the actions you've done (I hope the logs where enabled by default though).
But we could check the server configuration too : under Server \ Apache Webserver, you have created a Virtual server there should be set the web root path
Edit: Sorex provided the link to setup the directives
Edit: and about applying changes, in Webmin \Apache Webserver at the top right, you have links to start, apply changes and stop Apache directly (no needs to restart the Pi)