I started over again 3 times.
If you followed the steps to make a custom template you can copy the original tlp_header.php file from your default_template/common folder over to "your_custom_template"/common folder again and start over.
I am not sure how to obtain the actual untouched file if you did not use the override system, at least not if you got the shop installed on your server for you like I did by my server host.



