how do I fill in the following empty fields in the MySQL setup in zp-config.php?

• MySQL admin user
• MySQL admin password
• MySQL database

I am a total newbee and dont even know what MySQL is? ;-(

Well, you will probably have to learn

Zenphoto requires a MySQL database to operate. You must create that database before you can install Zenphoto. You will create it on some server and to create it you will need to log onto MySQL on that server with some user name and password.

So, when you have done that you will have all the things you need to answer the above questions.