Hi, when I started with Autodesk inventor one thing that help me so much is the learning path. All basic things you can learn there.
You can find when you open the inventor. There you will learn how to make a model, how make assemblies, how make presentations and 2D drawings.
I am a brasilian, so I don't know about youtubers that teaches in English. But you want to have a adventure in other language, search about "Professor Daniel Severino" and put subtitles in English. He is a nice brasilian youtuber, I learned so much with him.
Good studies and welcome to Inventor family :)