Start with a smaller, prebuilt module or one shot. You can find many of these for free on the DMs Guild. These adventures will help wet your feet with running a story, developing some plot, orchestrating combat, etc. You will likely observe "behind the scenes" notes and understand simple vs complex preparations that may lie in wait for players.
Even without the opportunity to run these games, read through a few adventures to get a feel. I believe it would be quite helpful.
You may also want to view some of the video posts created here on D&D Beyond: https://www.dndbeyond.com/posts
A few of these include: