Salat al-Tasbih is a four-rakat prayer. This prayer was taught by the Messenger of Allah (peace be upon him) to his uncle, Hazrat Abbas (may Allah be pleased with him), as a gift and present. Its virtue is that by performing it, all sins (small and large) are forgiven. There are two ways to perform this prayer:
One way is to make the intention for four rakats of Salat al-Tasbih, then stand in the first rakat and after reciting Thana, Ta'awwudh, Tasmiyah, Surah Al-Fatiha, and another Surah, recite this Tasbih fifteen times before going into Ruku: "سُبْحَانَ اللّٰہِ وَالْحَمدُلِلّٰہِ وَلَاإلٰہَ إلَّاإللّٰہ ُوَاللّٰہ ُأکْبَرُ". Then in Ruku, after reciting " سُبحَان َرَبِّي َالعَظِیْم", recite the Tasbih ten times. Then in Qawma, after reciting " سَمِعَ اللہُ لِمَنْ حَمِدَہٗ", "رَبَّنَالَکَ الْحَمدُ", recite the Tasbih ten times. Then in the first Sajdah, after reciting " سُبْحَانَ رَبِّیَ الاَعلٰی ", recite it ten times. Then after rising from the first Sajdah, recite it ten times in Jalsa. Then in the second Sajdah, after reciting " سُبْحَان َرَبِّیَ الاَعْلٰی", recite the Tasbih ten times. Then while rising from the second Sajdah, say " اَللہ ُاَکْبَرْ " and sit down and recite the Tasbih ten times. Then without saying " اَللہُ اَکْبَرْ ", stand up for the second rakat and complete the second, third, and fourth rakats in the same manner.
In the Qada of the second and fourth rakats, recite the Tasbih ten times first and then recite At-Tahiyyat. Recite the Tasbih in all four rakats in the same order. In this way, the total number of Tasbihs in four rakats will be three hundred times.
The second method is to stand in the first rakat and recite the Tasbih fifteen times after Thana. Then after reciting Ta'awwudh, Tasmiyah, Surah Al-Fatiha, and another Surah, recite this Tasbih ten times before going into Ruku. Recite the Tasbih ten times each in Ruku, Qawma, first Sajdah, Jalsa, and second Sajdah. After that, say "اللہُ اَکبَر" and stand up straight.
Recite the Tasbih in the second, third, and fourth rakats in the same order. Recite the Tasbih fifteen times as soon as you stand up in the second rakat. (Sunan al-Tirmidhi, Abwab al-Witr, Bab Ma Jaa fi Salat al-Tasbih, 1/117, Qadeemi) Perform the remaining rakats in the same order. Both of these methods are correct and practicable. Whichever method seems easier should be adopted. This prayer has no specific time; it can be offered whenever possible, except during Makrooh times. Only Allah knows best.
Mufti Sadiq Amin Qasmi