If you're unable to access The Modern Method, there is a way to get around it, especially if your school is using GoGuardian.
Note: If your school's firewall blocking is on the network, then it doesn't work.
TD;DR
Click on this URL (I suggest you bookmark it): https://storage.googleapis.com/penguinsareawesome-tmm.appspot.com/index.html
How it works:
The link above is using a simple iframe tag, to bypass the GoGuardian extension. (Yes, a simple iframe. Shame on you, GoGuardian)
What's a tag? A tag is an element used to display stuff, like this text right here.
What's an iframe? It is like a "mini-browser" in a webpage. It's like a webpage within a webpage.
How can I do "back" and "forward"? If you click in the iframe, you can use native shortcuts (ALT+Back/Forward).