This us a great addon I discovered recently, but nevertheless they have an introductory video about the Blender editor: https://github.com/GDQuest/blender-power-sequencer/blob/1.5....

I'm showing my bias but my good friend Andrew runs Blender Guru on YouTube. Admittedly he covers everything from beginner to advanced so I don't know where your skill level sits, but Andrew has a lot of content.