Honestly just go for it. I had no idea what I was doing the first time that I dm'd. Just let people know going in that "hey this is new to me, there might be some hiccups and slow downs but we will figure it out."

If you don't know just say that. I've been a dm for like 15 years and I still have to stop the game sometimes and be like "look I have nothing planned for this you guys have to give me a minute." Also worst comes to worst, just do what all great dms do, steal from other content.

I have gamepass so it is what it is

while that is true, finding and joining new /c's is klunky atm and not set up in a way that makes large growth likely