I made a new site under themes/miisound/
If i update the template after a change with ?flush=1 It works perfectly.
But i added a php file (HomePage.php)under themes/miisound/code/ as the tutorial told me to do.
When i do this: www.miisound.com/db/build?flush=1 , i see that it will run the script but no changes has been made. I also checked the backend and no other page type or contenttype has been added.
I tried to add another one in the code folder sitemap.php from another tutorial. but still nothing change after the flush.
SS will not pick up code that is in a folder which has no _config.php file, hence putting it into mysite
so in short, move your HomePage.php to the mysite/code folder
In the folder miisound/, did you create an empty _config.php file? The presence of a _config.php file tells SilverStripe that there is stuff in the code directory to process. If you don't have the _config.php file, SilverStripe will simply ignore anything in the code directory.