Kindly reference the following links:
Are the Sunnah prayers 'Must' for the validity of the five daily prayers?!
Encouraging to pray sunnah prayer | Assim Al Hakeem
Reward for praying 12 rakahs Sunnah Prayers: A house in Paradise (Jannah) | Sheikh Assim Al Hakeem
Must we pray 12 rakahs of sunnah once or everyday to get reward of house in Paradise
Reward of praying 4 rakahs of sunnah prayers before & 4 rakahs after Dhuhr
How to seek Jannah? (refrain from haram, pray fard prayers, voluntary good deeds)
Muslim Prayers(fard, sunnah, night prayer and witr) | Assim Al Hakeem
What are the Sunnah Al Rawatib prayers?