How to perform Qiyam al-Layl and Salat al-Tahajjud?

Tahajjud is a voluntary prayer performed at night after sleeping. It is also said to be the prayer performed after ‘Isha, even if before sleeping. According to this latter meaning, it is synonymous with Qiyam al-Layl (night prayer). However, according to the first meaning, it is more specific than Qiyam, as ‘Umar (may Allah be pleased with him) said: “That which they sleep through is better than that which they stand for.” Many jurists use the term Tahajjud to refer to night prayer in general, and its manner is the same as that of Qiyam al-Layl.