I’m a new DM, please give me tips

Hello! I’m going to be trying out DMing soon, and I have zero experience with that. I’m also new to DnD(but so are all my friends I’m playing with) I really don’t want to disappoint them or make the game boring. I already wrote a one-shot(or a concept of it anyways), but I need some tips on how to keep it flowing, when to roll what, and on just about everything else!