What prevents you from getting back?

What prevent me from getting back is not knowing how to do that - which is why I asked the question in the first place.

(Revised to be a little clearer)

If you load page1, load page2, then use back to return to page1, in order to return to page2:

• If Firefox has not gone forward to a different page, tap the menu and look for the forward arrow.

• If forward is not available, the page you went back to may have redirected, overwriting the forward history. In that case, use regular history: tap the address bar, change to the History panel, and find the page you were looking for.

Yup, that works; thank you.