Help with layouts coding

Hello! 

I love the freedom of customization that this web offers and I'd like to learn how to create great layouts that fit my liking, but I don't even know where to start. 

It's probably not as hard as it seems, but at first sight it looks so complex that I don't even know what I'm looking at . ╥﹏╥

So, I wanted to ask if anyone who has experience with coding here could give me some tips to start creating my own layouts instead of just using other's without knowing what all of those words mean. 

Thank you in advance! (﹡ˆ﹀ˆ﹡)♡