Completely lost in project fotomatic solutions

Hi, I am completely lost in project Fotomatic solution, which is focused on responsive design. I don’t know where to start. Could you please send me small piece of advice, where to start?
https://www.codecademy.com/paths/learn-how-to-build-websites/tracks/responsive-design-and-accessibility/modules/css-documentation-and-debugging/informationals/f1-2-c1p1-fotomatic.
Thank for every help.
Pipi

Hi,

for me starting at the top (header / nav) and working your way down worked out well.
Maybe it does for you too.

Paul