As
@Supcom said, your car will periodically check by itself and when there's an update you'll get a notification on your phone and you will see an orange "update waiting" icon on the top of the display in the car.
You can also force it to check by going to the software tab in the "car" menu. The act of opening that menu causes it to check - you will see a spinning icon for a few seconds, then it will either show you the update or it will say "Your software is up to date"
As others have mentioned. It takes a few weeks before a new car gets its first update.
Also, they don't do updates like Apple (i.e., everyone can get the update the date/time its released). They typically stagger them over a few weeks - they almost never roll out to all cars at once, so almost always you will see others posting online that they got a newer update than you have. For example, you will see 2022.12 go out to a few cars... then a few days later 2022.12.1 will come out and go out to a few more... this may repeat over a few days as Tesla makes sure there aren't major bugs or issues... then at some point they open the flood gates and the rest of the fleet gets it, Sometimes that takes a few days or a few weeks. It varies.
Just be patient. Sometimes you will be among the first to get a new version, sometimes you will be near the end, most of the time, you will get it within a week or so of first seeing it posted somewhere online.
If you're super curious you can follow the TeslaFi software tracker which posts stats on software versions seen by their subscribers:
https://www.teslafi.com/firmware.php When I look there I am currently on 2022.12.3.2 and I see three versions newer than what I have.
