Please tell us what you are trying to attempt. The 3 bar menu is available on the desktop version of Firefox and not Android. Please make sure the article you are reading applies to your device. You can also see Firefox menu icon is missing on Android - how to access the menu to know more.

I previously read the article you pointed to. There is no menu icon in the right corner. I trying to access FF setting to change (for example) search engine from yandex to google. As there is no hardware menu button on my phone (as I wrote: multitask, home and return buttons), and there is no menu icon in FF I have no idea how to change settings. I tryed to hold each of the present hardware buttons up to 10 seconds with no success. I attached the screenshot.

Nice phone. It certainly is device specific, as tested on other devices with Lolipop this does not occur. The three dots appear on the right of the tab. If you click on the number of tabs, does the three dot menu appear?

Thanks, the phone is really nice and cheap :) No, the menu does not appear even I click number of tabs.

kbrosnan confirmed that it will be fixed in 45, the nightly version of Firefox for Android can be found here: https://nightly.mozilla.org/