B minor chord (Bm or Bmin) consists of three notes. B (root) – D# (minor third) – F (perfect fifth).

B is the lowest key note in root position. To play Bm in root position, thumb (first finger) should be on B , third finger on D, and fifth finger on F# for Right hand. For Left hand play B note with fifth finger, D with third finger and F# with thumb (first finger).

D is the lowest key note in first inversion.
Play D with first finger (thumb), F# with middle finger and B with fifth finger for Right hand.
Play D with fifth finger, F# with middle finger and B with first finger for Left Hand.

F# is the lowest key note in second inversion.
Play F# with first finger (thumb), B with middle finger and D with fifth finger for Right hand.
Play F# with fifth finger, B with middle finger and D with first finger for Left Hand.