It is fard  for every Muslim who is sane and has reached the age of puberty to perform the five daily prayers. When a prayer time comes, it becomes fard for him/her the moment he/she begins performing the prayer. If he/she has not performed it and if there is time left enough to make an ablution and begin the salat before the prayer time is over, it becomes fard for him/her to perform it. If the prayer time is over before he/she has performed it without a good excuse not to do so, he/she will have committed a grave sin. Whether he/she has had a good excuse or not, qada  will be necessary. The same applies to situations such as when a child reaches puberty, when a disbeliever or a renegade becomes a Muslim, when a woman becomes canonically clean, when an insane or unconscious person recovers, and when a sleeping person wakes up.
It is fard for a new Muslim to learn the principles of salat first. After learning them, it becomes fard to perform salat. Sleep is not a good excuse if it begins after the prayer time has begun. If a person does so, it is fard for him to make sure that he will wake up before the prayer time is over, while it would be mustahab  for him to make sure to wake up before the end of the prayer time if he were to go to sleep before the beginning of the prayer time. These five daily prayers add up to forty rak'ats (units), out of which seventeen are fard, three are wajib (essential, almost obligatory), and twenty are sunnat  , as follows:
1 - Morning prayer [Salat-ul-fajr] consists of four rak'ats. First, two rak'ats of the sunnat prayer are performed. Then two rakats of the fard prayer are performed. The sunnat (the first two rak'ats) is very important. Some scholars classify it as wajib.
2 - Early afternoon prayer [Salat-uz-zuhr] consists of ten rak'ats, the initial sunnat consisting of four rak'ats, the fard consisting of four rak'ats, and the final sunnat consisting of two rak'ats. The early afternoon prayer is performed in this order.
3 - Late afternoon prayer [Salat-ul-'asr] consists of eight rak'ats. First the sunnat, which consists of four rak'ats, and then the fard, which consists of four rak'ats, are performed.
 fard: an act or thing that is commanded by Allahu ta'ala in the Qur'an al-karim. Fard (or fard) means (any behaviour or thought or belief which is) obligatory. Islam's open commandments are called fard (pl. faraid).
 qada': i) decree of a qadi (Muslim judge); ii) performance of an 'ibada after its due time.
 mustahab: (act, thing) deserving thawab if done but no sin if omitted, nor disbelief if disliked.
 sunnat: i) act, thing that was, though not commanded by Allahu ta'ala, done and liked by the Prophet ('alaihi 's-salam) as an 'ibada (there is thawab if done, but no sin if omitted, yet it causes sin if continually omitted and disbelief if disliked; the Sunna; i) (with fard) all the sunnas as a whole; ii) (with the Book or Qur'an al-karim) the Hadith ash-sharif; iii) (alone) fiqh, Islam.