Homey dash...how can i modifed?

ok so…
i have homey dash working and all good
i recently came across this guide
is there a guide or something more specific for someone who the name “node red” doesn’t tell him to much ?
i want to customized my dash but i have zero knowledge in “programming”
is there a way i can create something simmiler to what the guy in the post created?

for example… i wanted to change the background of my homey dash and i didn’t understood what url i need to put to change the background