Usually it's at the bottom near the "power" (exit) icon. I'll attach a screenshot for reference. Note that your set of icons on the menu probably differs from mine and everyone else's, so don't worry about that.

You also can access the Help menu on the classic menu bar. To activate the bar temporarily, tap the Alt key or the F10 function key.

Are you referring to the ? (Help) item in the "3-bar" Firefox menu button drop-down list?

You can also open "Help > About" via the Help menu on the Menu Bar. You can tap the Alt key or press F10 to show the Menu Bar.

Note that not all users will get an update offered and it is normally throttled during the first week. There is usually first a small selection that gets the update offered to make it possible to check for issues that weren't noticed during testing.