You are probably familiar with some of the aspects of the ritual.
For example, using mantra in Vajrayana ritual means that we recite certain sounds (om … ra ... ram … hum ... etc.) over and over to establish unity with the Buddhist deity.
And in the same way we adopt the mudra that is particular to the deity. So we are likely to hold our hands in a certain way, which will invoke that deity because that deity is always identified with that mudra.