Joining the Imam in the Last Rakah
How should I complete my prayer in case I join the congregational prayer in the last rakah (unit of prayer)?
It was narrated that the Messenger of Allah (peace be upon him) said, “Whenever you come for the prayer, you should come with calmness, and pray whatever you get (with the people) and complete the rest which you have missed.” (Al-Bukhari)
A person who joins the imam or the congregational prayer after the first rakah is called masbuq (late comer).
1- Standing up after sitting for tashahhud with the imam.
2- Reading Surat Al-Fatihah (the Opening Chapter) and some verses from the Quran.
3- Siting after the ruku` (bowing) and sujud (prostration) and reading only At-tahiyyat.
To know the remaining steps and more about joining the imam in the fourth rakah of prayer, you can watch this short video with Dr. Asim Al-Hakeem.
Source: Huda Youtube Channel.