Going back to previous page to complete lesson?

[rlv57]

I was right near the end of a lesson on my iPad. I needed to turn on the mic for the lesson, which required Adobe. I clicked the link and got the page that said iPad doesn't support Adobe. There was no return to lesson link, so I hit the back button to return to my lesson and it was GONE! How do I return when leaving the lesson page for a moment without losing all my work?!