All right, here you go!
As you have no doubt figured out the marbles are magnetic. But what you probably don't know unless you opened one up is that the magnet is not round but a cylinder shape , this cylinder has a North and South pole, but in the middle the strength of these poles is at it's weakest. This means that if you place all of the marbles with the cylinder facing up and down that the pull from around it will be at it's weakest.
So how can you tell which way it should face?
Simple, the seam of the marble is where the weakest point is, so just make sure all the marbles have their seams horizontal (level to the floor as shown in the animation). With the secret the puzzle will be fairly simple to complete, you must have a flat, level surface, a steady hand and nerves of steel to complete the puzzle. Now that you have the solution you can make it look easy to others by solving it quickly, but when they try, the fun begins!