1. Eclipse of the sun
2. Eclipse of the moon
3. Earthquake
4. Thunder and Red & Black storms

People must start saying Signs Prayers from the beginning of Eclipse of the Sun or Eclipse of the moon. There must not be any delay in saying Signs Prayers and it must be performed, before the elimination of the sun eclipse or the moon eclipse. People must say Signs Prayers immediately at the time of earthquake and thunder or etc. If one's doesn't say Signs Prayer, he/she disobeys God and it is obligatory for him/her up to the end of life.

Niyyat (Intention)

Saying "Allahu Akbar"
Recite the opening chapter of the the Fatiha and then immediately follow up this by reciting "Sura"
Bowing in Ruku' and after that one Hamd and Sura
Again one bowing and one Hamd and Sura up to five times
After the fifth bowing, two prostrates (Sajdah)
After 2 Sajdah, stand and recite the second rak'at just like the first rak'at and say Tashahhud and Salam.

Another method of saying Signs Prayer is:

Niyyat
Allahu Akbar
Reciting Hamd & Sura
Dividing verses of a sura to 5 parts, reading one or more verses of it, go to bowing, read the second part of the same verse, go to bowing, and continue in this way so that the sura could be finished before the fifth part of it.

For example:
Saying: Bismillah-i-Rah-man-ir-Raheem, go to bowing, and stand after bowing and say: Qul huw-allahu Ahad, go to bowing, and stand after that and says: Allahus-Samad, go to bowing, and stand after that and say: lam yalid wa lam yoolad, go to bowing, and stand after that and say: wa lam yakum lahoo kufuwan ahad. One's must do the fifth bowing and after that two prostration, recite the second rak'at just like the first rak'at. After the second prostration one must say Tashahhud and Salam