Bismillahir Rahmaanir Raheem
1. It is Sunnah to use the Miswaak at the time of every Wudhu
(Abu Dawood, Volume 1, page 8)
2. The Sunnah method of holding the Miswaak according to what Hazrat Abdullah Ibn Mas’ood (RA) has narrated is as follows:
Place the small finger of the right hand below the Miswaak. Place the thumb below the head of the Miswaak. The remaining three fingers will be placed above.
(Shami Volume 1, page 85)