How Do I Pray A Four Rak`at Sunna Prayer?
For the fard salah, one recites a sura after the Fatiha in the first two rak`as only. In the first first sitting, one recites al-Tahiyyat only.
For four-rak`a sunna mu’akkada prayers (i.e. the sunna before dhuhr and the sunna before and after Jumu`a) one recites a sura after Fatiha in all rak`as. In the first sitting, one recites al-Tahiyyat only.
For four-rak`a non-mu’akkada sunna prayers (for example before Asr), each two rak`as is like a separate prayer, though they are offered with one taslim only at the end. This means that in addition to reciting a sura in all rak`as, one would also recite the durood after al-Tahiyyat in the first sitting, and recite the thana’ (opening invocation: subhanakAllahuma wa bihamdik…) and ta`awwudh (a`udhu billahi…) at the beginning of the third rak`a.
In the last sitting of all prayers, one recites al-Tahiyyat, durood, and d`ua.
By Imam Yasar Malik