So, I am not trying to sound mean but if you do not understand how to get the game to show then it might to be too much for you at this point.
Yes, you use a editor to write your code in. There are a ton of editor out there, and people have different preferences on which ones to use. For me, I use visual studio code and like it a lot. Before that, I use to use sublime text and it also got the job done.
Before you try creating the game I think it would be a good idea to go through the curriculum here, or if you can spare $15 look at some classes on udemy. They will walk you through everything, personally I like the instructor Colt Steele on the platform
Start small and work your way up to this! You’ll have more fun if you really understand the basics well. I’m still relearning the basics and find that each time I review it I notice things I missed the first time around.
I watched the beginning of that video you mentioned and she does state that some basic JS knowledge is required as she isn’t going to go into much detail about teaching the basics.
I also recommend Colt Steel on Udemy, I went through his Bootcamp course and found it to be an awesome supplement to the material available on freeCodeCamp.
VS Code is an extremely popular editor with coders and it’s free. If you look on youtube, I’m sure they have videos on how to install it and can probably find a tutorial on writing and running a simple JS app on your computer, in a node terminal. It seems scary, but it’s pretty simple.