Thx @texnixe, @thguenther, @manuelmoreale and @pedroborges
First I prefer a mix of videos and reading. I like both and learn with this mix really good.
Second, I will look at all your suggested websites in the next days.
I love the work with Kirby but actually without a really understanding what I do. I want to change this and will learn more about php and so on.
So, when someone has more good sites then I’m happy to read them.
P.S.: Next week I will write something about the working process of my website.