Try the following: Drop the metal ball into the shaker, fill a bit of water in (just enough to cover the ball, then drop the powder on top. After that slowly fill the shaker to the rim with water (Fill it as much as you can so nothing spills).
Then shake heartily for a while, open the shaker and wash any residue off the white cover (Trust me on this one) and enjoy your shake.
Don't let it sit too long, or you'll have a thick slimy consistency.