Hi Aris,
1. Before you do the synchronization of the ailerons you want to make sure that the servos are working in the same direction when connected and also have about the same travel on the surfaces. You can do this by connecting them mechanically one at a time and make sure they have about the same travel and mid point.
2. You make a choice of which servo will be the master and which will be the slave. E.G. left side master 1 and slave 1 - right side master 2 and slave 2. If you have a stronger servo, then you use that as the master. Please also refer to the manual. You can create up to 16 segments in the curve of the master servo. The synch feature will do a synch at every point. After the synch, the slave servo will have a similar curve in it. You can also create these points on a straight line. It will help to compensate for differences between the individual servos. One tip, If you call all involved servos to be a slave of the first servo, it will duplicate the curve into the configuration and keep it even after you rename it to master 2.
3. Once done with both ailerons, you connect everything mechanically and hit the synchronization button. It will run through the curve one side at a time, returning to middle again at the end.

Once mor I want to point out to look at the instructions as well, as they go through this process as well.

Thank you and Merry Christmas to you and your family,

Gerhard