If you have enough experience to make your own custom adventure for your players, I’d recommend that, so that you can easily adjust it to suit your players needs and preferences.

But if if you’re not comfortable with that, then probably just use the campaign that comes with the d&d starter pack (lost mines of phandelver or something like that).
It’s not an especially amazing campaign, but it has a decent mixture of dungeon crawling and roleplaying, and the story/encounters are simple enough for beginners to understand. It’s a safe bet to ease players into TTRPG.

You could also try a totally different system. I hear good things about Blades in the Dark. I’ve never played it, but what I hear sounds like it avoids overwhelming new players.

For first timers? None of them.

Make up a basic introduction quest.

How did the players meet each other? Why are they adventuring together? What are these characters all about?

If you can get the players to connect with their characters right off the bat, they’ll be much more likely to come back for session 2.

I like to start them in a small town of little consequence. Throw in everyday challenges, like a tavern bully, or “we need $X by end of day”. I might have some ideas of buildings and people in the town, or some low level monsters to fight, but keep it casual. Let the players guide you at first.

If you force them to push through a pre written quest that assumes they already have a grasp on the game, they aren’t going to find the clues that the rest of us would think are pretty obvious. I’ve tried it before, thinking “if I give them a professional module, they’re getting the best experience,” but I had to hold their hand and pretty much tell them what to do, and nobody felt like they were playing their character, it was more like sitting through a Disney interactive ride. They were just watching it go by and waiting for me to tell them what should happen, and I don’t think we even finished the quest.

Let them be silly, let them experiment and learn that they can do things here that they can’t in real life, but their choices will have consequences.

Good luck! Have fun!

I would double down on the starter packs such as Lost Mines of Phandelver or Dragon’s of Icespire Peak. They are pretty basic and open enough that you can change or add on things that people are interested in. That only if you want to use an official campaign.

I would really recommend making your own campaign. Its really not as daunting as it seems. All you really need to do it make a single adventure and see what people like. From there see what parts people interact with and expand on that. I explicitly ask my players what they like, what they want to interact with and expand there. You can throw a bunch of ideas that you think might be fun into an area and see what ones people like. This is what I have been doing for the last few years and its been much less work than I expect. Also the player interaction is really engaging especially for new players. They can see that unlike a video game you can interact or change the world. Best of luck!!!

I made a small, one-session adventure called “The Lost Moo”. Players immediately got suspicious when they saw the title. And yes, it is about stolen cows. Sorry, no heroic dragon fight and hoards of treasure for a first-level adventure ;-) Just a bunch of faeries “borrowing” cows to lure adventurers into their forest to take care of a problem they have.

The idea behind this adventure was to offer a bit of everything: City adventure with NPC interactions, overland (and into the woos) with tracking and orientation, traps, riddles / problem solving, a dungeon, and finally, a fight.

This was designed that way to see how the players deal with the different scenarios of playing and to see which suits them and which doesn’t. I adjusted the next adventures accordingly.

I’ve had success with this in exactly this situation

https://winghornpress.com/adventures/a-wild-sheep-chase/