I've wrestled with making this blog post(let alone my first one!).
Look, I've visited global and block scopes before, in fact in a boot camp I left I was taught it. Do not ask me why but I did not understand it when it was taught. It may be I'm not good at soaking in ideas as I listen to them but rather need to be able to implement them at my speed. To that end, Codecademy has been a huge boost.
Here's a bit of code, the global scope is everything outside curly braces. Literally everything in the curly brackets is block scope.
Think of it this way, "const twitter = '@mynameissalah'" is an h1 tag & everything in curly brackets is the css for the h1. That is to say, the curly brackets much like the css both respectively add a functionality to the parent they are assigned to.
I hope this helps at least one person! I feel like I was the outlier who didn't understand this easily while others seemed to—until it clicked & it was wildly simple. I don't learn as easily as most people & if that's you as well, hi! Wishing you the best in your learning, be easy on yourself. :]