If forgetting to recite Tashahhud during Salah, what one should do

Q 4: What is the ruling when a person forgets to recite the first Tashahhud (a recitation in the sitting position in the second unit of Prayer) but then they remember or are reminded? Please tell me what such a person should do if they remember the first Tashahhud (Part No. 6; Page No. 8

A: When a person remembers the first Tashahhud before standing up fully, he as to return to the sitting position and perform it. If he remembers the first Tashahhud after standing up fully but before starting the recitation of Surah Al-Fatihah; it will be Makruh (disliked) for him to return to the sitting position to perform Tashahhud. Besides, if they remember the Tashahhud after starting the recitation of Surah Al-Fatihah; it will be Haram (prohibited) for him to return to the sitting position. However, the person in question has in all cases to perform Sujud-ul-Sahw (Prostration of Forgetfulness).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.