For you, Snapchat is almost guaranteed to be an app you'll use to watch video, and perhaps even publish some of your own.
That's why I'm showing you this tab first: Stories is Snapchat's killer tab.
It's filled with a ton of media — mostly video — broken out into three categories: 1) Discover (from media companies), 2) Live (curated by Snapchat) and 3) Recent Updates (mostly from your friends, but also from brands should you choose to add them).
You'll find Stories by swiping left on Snapchat's camera screen, the first screen to appear when you open the app.
Though I'd installed the app on my phone, I had no idea how to use it, and little interest in doing so.