Real quick about querySelector() and getElementbyId() first.

Manipulating the objects on a screen is a great way to begin to understand what the abilities of knowing the language can do. Using the dev tools you can temporarily make changes to html and css of a page as well as run javascript in the console.

Using the console is a fun way to learn javascript and to see the code you write change the DOM in real time. You can find an element on a page, and assign it a new value.