What does the sign of the cross mean and why do Orthodox make it?

The sign of the cross comprises a couple of elements. The two fingers tucked into your palm are the two natures of Christ, divine and human. The three fingers together are the three persons of the Trinity, the Father, the Son, and the Holy Spirit, not assigned to a finger, but all three persons together. And then the fact that we love the Lord our God with all of our mind, with all of our heart, and with all of our strength.

Why do we make the sign of the cross? There is power in the sign of the cross. That's essentially it. Many people under attack from demons have made the sign of the cross, and the demons flee. It has power because Christ was crucified on it.