Layout? Not sure what do. S.O.S

OK. SO.
If you see my recent stories the layout is some classic Mibba crap that I don't even know.
I dont know how to work this layout thing and for some reason I can't indent paragraphs? Wuht. I can't even.
I am confused and feel like a lost puppy in a big city. Anyone wanna help me out here? Is there a way to create it or something? I mean I found that layout page where it's just like "preview!" "Use it!" but I'm still not sure what to do and that Mibba classic layout is really killing me.
Thank you whoever can help clear this up for me! I'm just becoming active again so I have a lot to learn.