How can I activate the accessibility menu?

The Accessibility Menu provides a large on-screen menu to control your phone. You can control gestures, hardware buttons, navigation, and so on.
1) To use this feature, system navigation buttons should be enabled: go to “Settings”->”Button & gestures”->”System navigation”->”Buttons”.
2) Then go to “Settings” -> “Accessibility” -> “Accessibility Menu” ->touch the toggle to “On” position->touch “ALLOW” -> the accessibility menu icon will appear on the navigation bar.