How is Fajr prayer performed? Is it two rak'ahs with the intention of the Sunnah of Fajr, followed by two rak'ahs with the intention of Subh, and is it prayed aloud or not?

The obligatory prayer at that time is the Fajr (Dawn) prayer, two cycles (rak'ahs) recited audibly with Al-Fatihah and whatever else is easy from the Qur'an. It is sunnah to pray two cycles before it, which are the Sunnah of Fajr (Al-Raghibah).