You can find unofficial adventures online, but some of the published campaigns have "introductory" adventures like the "Death House" for Curse of Strahd, which is pretty straightforward and runs the players from level 1 to 3.
There are lots of One-Shot adventures that are necessarily self-contained.
Dragon of Icespire Peak, from the starter set, if you're looking for WotC material. There's tons more to be found very easily on dmsguild though.
Want to start playing but don't have anyone to play with? You can try these options: [link].
You can find unofficial adventures online, but some of the published campaigns have "introductory" adventures like the "Death House" for Curse of Strahd, which is pretty straightforward and runs the players from level 1 to 3.
There are lots of One-Shot adventures that are necessarily self-contained.