Make it more obvious how to navigate back to step 1

[joanise]

Reported by Delaney:

In her first tests, she didn't immediately figure out how to navigate back to step 1, so she tried to browser's back button and lost data.

I'm not sure what the best solution is. Long term, we should make the back button actually go back to step 1. Short term, maybe add a second redundant button at the bottom of the page saying "Go back to step 1 (erases images and translations)"? The tour addresses it, but it's still a gotcha.