The correct opinion is that you can pray Tahiyyat al-Masjid at all times, even after Fajr and after ‘Asr because of the general applicability of the hadith “When any one of you enters the Mosque, he should not sit down until he has prayed two rak`ahs.”

This is how to pray istikharah: 1. Make wudu (ablution) 2. Offer two rak’ahs of sunnah prayer 3. Make the du’a mentioned in the detailed answer below.

The confirmed sunnah prayers are: 1- 4 rak’ahs before Zhuhr; 2- 2 rak’ahs after Zhuhr; 3- 2 rak’ahs after Maghrib; 4- 2 rak’ahs after ‘Isha; and 5- 2 rak’ahs before the Fajr.