Part 2 of the scripting tutorial series features changing scene through code, creating a custom menu scene and creating a custom window for the scene. Nothing fancy right now, but you have to start somewhere.
If you have any questions, feel free to leave a comment. I'll try my best to answer.
P.S Sorry for the cutting fails, but I don't make my videos to be pretty, but to be useful :P
Useful links:
RPG maker MV corescript:
https://github.com/rpgtkoolmv/corescript
Kinoar's documentation:
https://kinoar.github.io/rmmv-doc-web/index.html