There are some mantras taught in the course which can be used for a practise to leave body. It might however be best to wait until that time, since they would contain sound files so you know how they are to be prenounciated and vocalized.

In the meantime mantras are only one of many forms of techniques used for leaving body. As the essence of a practise to leave body entail a good level of relaxation and a strong mental focus/concentration. This concentration can be put on a number of techniques, such as visualizations, mantras, sounds, repetive statements/words etc.