First campaign advice

Hey all! I’m looking for some advice to run my first campaign. I’ve also never played a true campaign game, only a few solos or two player games. I live in a rural town and it’s hard to get people interested. Anyway, I managed to convinced a few friends to play Bullets and Bourbon with me (Campaign game based on the Jefferson Territories where game mechanics are determined using a deck of cards). I barely know what I’m doing but want it to go well because I’ve always wanted to get into ttrpg.

I studied all day and feel I have a decent handle on game mechanics, combat/challenges, and I’m looking for advice on how to weave a story together, improvising advice, and how to teach people that are as new as myself. Do I make a bunch of NPCs ahead of time?

Any advice is welcome but please be kind! (If not you may scare me away from ever trying again ha)