Method of Salaah

Q: If I am reading 4 rakaats Sunnah salaah and I read surah Naas in the first rakaat, what must be read in the remaining 3 rakaat?

Q: What is the correct way of tasleem in namaz. What I know is, at the end of salah, should I start saying salam (assalamu alaikum wa rahmatullah) when my head is towards the qibla and continue saying salam while I turn my head towards the right and complete saying salam after I complete turning my head. This completes the first salam. Should I turn my head towards the qibla then I should start saying salam when my head is towards the qibla and continue saying salam while I turn my head towards the left and completes saying salam after I complete turning my head. This completes the second salam.

I have observed the following three cases in case of three imams who are leading prayers. Could you please clarify if the salah is valid in these cases.

1. At the end of salah,the imam turns his head towards the right and after completely turning he says salam. Then he turns his head to the left after completely turning he says second salam. Is salah valid in this case? Why I am asking this question is , I have read somewhere (I guess it is from a shia person) that if you turn your head during salah your salah will become invalid. In this case the imam first turned his head to the right, by the time he starts saying the salam his salah has already become invalid.

2. The imam completes the first salam properly as per my understanding. But he starts saying the second salam when his head is turned towards the right and continue saying the salam while he turns his head towards the left and completes saying the salam after he completes turning his head towards the left. Is salah valid in this case?

3. At the end of salah, the imam completes saying salam when his head is towards the qibla then he turns his head towards the right. Then he turns his head towards the qibla and completes saying salam when his head is towards the qibla then he turns his head towards the left. Is salah valid in this case?

Q: My question is regarding namaz. I am offering Esha prayer and in the sajdahs of the first rakat i say "Subhan a rabi ul alaw" three times and in the sajdahs of the 2nd raka I say "Subhan a rabiul a alaw" 5 times. Is saying "Subhan a rabiul alaw" three or five times that make impact??

Q: When praying salah, in sajdah Zaid places the upper part of the toes (the part where the nails are on the toes) on the ground, is the sajdah and Salah valid?

Q: A person was offering fajr and recited Surah Al A'laa in it. However, the person missed 4 ayat in the middle of the surah (from ayah 12 to ayah 16) and also did not do sajdah sahw. Should the prayer be repeated?

Q: Is the following makrooh:

1. To read a shorter Surah in the first rakaat and a longer Surah in the second rakaat?

2. To read a Surah in the 1st rakaat and then skip a Surah and read the next Surah in the second rakaat?

3. To recite Surahs in the wrong order in salaah?

Q: I have been told that we cannot pre determine what surahs we going to read before commencing salaah. This came up when I told someone that I have first rakaat surahs, second rakaat surahs & so on, so I do not make a mistake or forget which rakaat I am currently reading.

Q: In the third or fourth rakaat of a four rakaat fardh salaah, a person mistakenly recited a surah after Surah Faatihah. If sajda-e-sahw is not made, is the salaah valid or does the salaah need to be repeated?

Q: Is it permissible to recite duas that appear in the Quraan in Sujood? Such as

رَبَّنَا آتِنَا فِي الدُّنْيَا حَسَنَةً وَفِي الآخِرَةِ حَسَنَةً وَقِنَا عَذَابَ النَّارِ

Q: I don't know the last durood that is read in last before salaam. What can I read inplace of that? I also don't know the dua in witr salaah. What should I do?