Q: Do we need to center and ground our chakra system before we start the vibrational awareness technique?
A: If this is something which feels necessary to you, then yes. The vibrational practice automatically has centering and grounding impact without us having to become mental about it. However, experiment and see what works for you. Let your experience always have the last say. Don't get too distracted by such metaphysical intricacies - or as I like to call it - mental-physics.