Hi Faye,
“Link in the description box below” is in reference to folks watching the video on YouTube’s website or app. There is a description box under each video that let’s creators put text or links in (you would need to click “SHOW MORE” to expand it):
But if you’re watching the videos on our site, you won’t need to use any of this as I link the most important (extra) lessons in the “Helpful Tips” section above the video:
As for your second question, check out the second video on this page and jump 6 minutes into it to learn how to use the tab player. That video also gives a rundown on how to navigate the site 🙂