Obligation of performing Sujud-ul-Sahw when the Imam sits for Tashahhud in the first Rak`ah

A: If the Imam mistakenly sits to recite the Tashahhud in the first Rak‘ah, they should offer Sujud-ul-Sahw before or after Taslim, because they added an action extra to those performed in Salah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.