When is sajdah sahw (prostration of forgetfulness) needed?

“The preferred view in the Hanafi Madhab is that Sajdah Sahw should be performed after making a one-sided Salaam. After performing the two Sajdahs of Sajdah Sahw, one will recite Tashahud, Durood Ibraheem and the Dua after Durood. Thereafter, he will make Salaam.”

“Sajdah Sahw refers to an additional two Sajdahs performed at the end of Ṣalāh due to forgetfully not performing a Wājib act of Ṣalāh or delaying performing a Wājib or a Fardh act of Ṣalāh. The scholars have mentioned ten principal rulings of the mistakes which necessitate Sajdah Sahw:”

“In principle, Sajda Sahw becomes Wajib (necessary) when one unintentionally misses a Wajib act of salah. If one misses out multiple Wajib acts in Salah, that will necessitate only one Sajda Sahw.”

“If a mistake which requires sajdah sahw occurs in salaah then after the tashahhud of the last rakaat, make one salaam to the right and make two sajdahs. Thereafter come back to the sitting position and recite the tashahhud etc. and complete the salaah as normal.”