Second of all, one of the most important things to a pianist, before you even start to play a piece. Learn how to curl your hands while hitting a few notes. Why? Because playing with your hands are curled and having your finger tips touching the keyboard enables you to play at a faster speed when necessary! While, flat fingers only makes you slower and affects your playing.
Curl your hands like shown below:
And REMEMBER to lift your wrists up while playing, because if your wrists collapse on the edge of the keyboard, it will affect your playing!!
That's it for lesson one. Hope these tips help! =)