Dear Brother, Al salamou alaikum!
in the last Rakaa of all Salah, we say the tashahoud full. (for all salah which might consists of two, three or four rakaat).
and only in the case of praying a salah which consists of more than two rakaa (3 or 4 rakaat like maghrib or Duhr asr and Eisha) we should say half of the tashahoud(till "ashhadou anna laa ilaha illa Allah wa ashhadou anna Muhammadan Rasoulullah") after the 2nd sujud of the second rakaa.
(and in the last rakaa we will say it again but in full)
so in the case of two rakaa, you will only say tashahoud once full at the last rakaa.
in the case of maghrib or Duhr, Asr and eisha, you will say half the tashahoud in the second rakaa and again but in full in the last rakaa.