Many of the gestures you already use to navigate around your Android device can be used in Firefox.
To zoom in and out on the page you are viewing, you can double tap the screen or use a pinching motion. To learn more about how you can use gestures to zoom, head on over to Zoom in and out of websites on Firefox for Android.
A long tap--touching and holding on the screen--will trigger the context menu for what is tapped on.
The Awesome Screen shows you tabs at the top for Top Sites, Bookmarks, and History. You can tap on each of these to move to that tab.
For Android 4.1 Jelly Bean and up: You can also swipe left and right on the Awesome Screen to flip through the three tabs.