The healer must determine the patient's frequency and attune it to the crystals that will place it in balance. All healing is about placing the body in balance. Treatments will vary in length and number of times required. They may not always work. It's always good to have a few quartz crystals around your home to balance the energies - before you need the healing.
Many people connect the color frequency of a specific chakra with that of the stone being used.
The person needing the healing would lay down - the blue crystals being placed on the throat chakra. The success of crystal healing varies with the person being healed. Remember that in all healing - one must address the emotional issues linked to the healing the physical illness can be permanently cured. Draws disease out of the body and transforms it. Remind one of the Ocean of Love and Mercy.