Paternosters were constructed quite differently from the modern rosary. A set or a pair of beads (singular) was typically made in either a linear form or a loop. They were usually strung on twisted or woven silk cord, that being the sturdiest, though sometimes woven wool or hemp cord was used. Most of the time the beads can be slid down the cord, and some Paternosters have quite a lot of slack... like this one we made that was directly inspired by an Italian painting:  

The number of beads, either in total or in sections, varied wildly. Some were in short lengths of ten beads, while other Paternosters have hundreds of beads. You may see them finished with a tassel, or a cross, or a crucifix, or two tassels, or a religious medal, or nothing extra at all. Medieval art presents a whole gamut of various styles of Paternosters. 

The most common materials for the beads used included wood and bone beads, but also frequently used were horn, glass, red coral, semi-precious stones, pearls, amber, and more. All of these beads were of course made by hand by skilled artisans, who usually specialized in working with a particular material.