:salam2:
I think you are asking about WITR prayer prayed during ISHA salat.
WITR prayer in the isha is composed of 3 Rakats.
You make three rakats asusal you pray 3 rakats for magrib except in 3rd rakat you perform few additional things. In 3rd rakats after reciting surah fatiha and and other sura before going into ruku say takbeer(Allahu Akbar) raise your hands to the ears and then fold again and recite Dua-e-Quonoot.
Dua-e-Quonoot:
Alla-hum-ma in-naa nas-ta-ee-nu-ka
wa nas-tagh-fi-ru-ka
wa nu-mi-nu bi-ka
wa na-ta-wak-ka-lu a-lai-ka
wa nus- nee a-lai-kal-khair
wa nash-ku-ru-ka wa laa-nak-fu-ru-ka
wa nakh-la-u wa nat-ru-ku mainy-yaf-ju-ruk
Alla-hum- ma eey-ya-ka na-bu-du
wa la-ka nu-sal-lee wa nas-ju-du
wa i-lai-ka nas-aa wa nah-fi-du wa nar-joo
rah-ma-ta-ka wa nash-sha
a-zaa-ba-ka in-na-a-zaa-ba-ka
bil-kuf-faa-ri mul-hiq
After reciting say takbeer again and goto ruku and complete third rakat as usual. Hope this helps.
There are many threads in this site which talk about how to perform salat. InshaAllah, I will try to find few and post references.