1- The correct view is that the regular Sunnah prayers are twelve Rak’ahs: 2 Rak’ahs before Fajr; 4 Rak’ahs before Dhuhr, with 2 Salams, and 2 Rak’ahs afterwards; 2 Rak’ahs after Maghrib; and 2 Rak’ahs after `Isha’.
2- Sunnah prayers should be offered individually except in cases in which the Sunnah is to offer them in congregation, such as Tarawih prayers.