Installation for an absolute beginner

dear forum
i am an absolute beginner concerning websites and co. the installation seemed easy to me … copy the data to the webspace. then I redirected the subdomain kanboard.mywebsite.ch to the folder kanboard.
but only an error message appears:
"Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, [no address given] and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log. "

Then I tried if it would work with a mysql database. database set up, connection data stored in config.default.php, renamed to config.php.

same error message …

Can anyone help me further? as I said, I am an absolute newcomer to this field …

my provider offers parallels confixx for the configuration of the web hosting

THANK YOU

There could be many reasons for an Internal Server Error. Try to check your error logs in parallels confixx to get further information.