I keep seeing lots of questions about Dreams that I feel should already be understood but I guess that's because I've followed it from the start. No doubt there are many people who only gave it a passing interest and are now only taking a look, so I'll post the most relevant vids for all the elements of the game/creation tool. Watch all of these and listen carefully and you'll know what you need to know.
Short form vids:
What Is Dreams:
https://www.youtube.com/watch?v=ia4LSiB3FYY
Introducing Story Mode:
https://www.youtube.com/watch?v=Nsj7I3Nbo7I
Making An Environment:
https://www.youtube.com/watch?v=zVII2JFp8Tk
Creating A Level:
https://www.youtube.com/watch?v=zYqSEzKIrw4
Long Form Vids:
Music Creation:
https://www.youtube.com/watch?v=E3BPsKb8p6I
Design And Logic:
https://www.youtube.com/watch?v=7B-uSuzbAjY
Cut Scenes, Animation And Puppeteering:
https://www.youtube.com/watch?v=9ihLm7bDkLk
The PS5 Exists.