How to add a parallax effect to an image or the background image of a container?

Hi

I need to replicate the parallax effect as seen on this page, right above the "Wie ich Dir helfe" section.

I have added the image to a container block and then applied Toms tutorial from GB-forum, but it's not the same effect, and also makes the container overlap the footer.

Could you please help me with this?

Thank you in advance and kind regards,
Sascha