Let's say that tomorrow you're going to build your first house, and you know nothing about building a house. You know nothing about construction, but you decide you're going to go ahead and build a house. Are you going to look into one of those fancy luxurious architect design magazines, pick a house and start to build it?
My guess is that you're probably going to start very simple.
With web design and WordPress, it is the same thing.
Even though you might have the desire to build the most sophisticated website inspired by what you see, keep in mind that most likely those fancy designs didn't get built overnight and might have required the collaboration of entire teams.
One of the best advices I can give at the beginning is to keep things simple.