fixed button in hero section

Hi, I am trying to put a fixed button in the first section of a client’s website as the Mercedes Benz page has it (https://www.mercedes-benz.com.mx/es/home), however, I cannot get it to stay fixed because when scrolling it scrolls up and I want it to stay fixed and have the second section cover it just like the Mercedes site.

(see sample site on desktop)

Thanks a lot

The page I need help with: [log in to see the link]