Piano Forum

Firstly, you've done *very* well to teach yourself that!  In my experience, people teaching themselves piano rarely works so well!

The one thing that absolutely jumps out at me is that your arms seem to almost leap up from the bottom of the key after every key press - it's almost like the video of playing it has been reversed!  While that doesn't matter so much on a digital piano, if you were to play like that with a grand, it wouldn't give you a very nice tone 

So ...  what you need to do (and it's horrible to try and explain with words!) is to imagine all the weight of your arms and upper torso (for the loud notes, anyway), relaxing right into the bottom of the key bed for each note you strike.  Keep your fingers on the notes, afterwards too - don't pull up out of them immediately so you're relying entirely on the pedal to keep them sustained - use as much finger legato as you can, too.

Hopefully someone else can explain all that better than I just did, anyway!  Do let me know if it raises any questions or difficulties!

All the best