Scales, five-finger positions and chords
In all 12 keys, with the fingers for both hands. Pick a key to hear it and practice it.
Scales
Major scale
Eight notes up and back down, the thumb tucking under so one hand plays the whole octave.
Natural minor scale
The darker cousin of the major scale: its third, sixth and seventh notes are one key lower.
Harmonic minor scale
The natural minor with its seventh note raised, for a strong pull back home.