Advise me! Just about to start learning Javascript

Hello dev community!
I just finished learning html, css, git, and bootstrap, and now I want to expand my frontend web development skills by diving into JavaScript. As a beginner, what are some of the best resources that I can use to learn Js?
Also, what are a must-to-know concepts of Js that I need to master to be able to land my first job as a frontend developer?
Note: I'm aiming at mastering vanilla Js before diving into js frameworks and libraries.