You can find general house piano techniques and "Stay Together" covers on platforms like YouTube to see the finger positioning for the main riffs.
The "funk" comes from the interaction between the piano and the bass. Practice playing the piano riff along with a metronome or a house drum loop to lock in the timing. Resources Stay Together (Funky Piano Mix)
The "Funky Piano Mix" relies on syncopated rhythmic stabs. Instead of holding long chords, play short, percussive hits primarily on the off-beats. You can find general house piano techniques and