How are Tephillin made?

Tephillin are a set of two leather boxes filled with parchments on which a scribe has written specific verses from the Torah, then attached the boxes to leather straps, each knotted so that one can go around your head and one around your weaker [non-dominant] arm. It is quite complex to make Tephillin, and one is best served by buying good quality ones made by a scribe.