Am I supposed to fill in the individual fields in the Setup → php → general options → Audit trail window ?
If yes - with what ?
Yes, otherwise the script does not know which fields to update to. See the topic PHP Settings → Audit Trail in the help file:
You can create the database yourselves and select the table in the combobox, then click the […] button to select the fields in your table. Alternatively, if you have not created the table yet, you can click [Create Table] and let PHPMaker creates the table and setup the settings for you.