Cleanse the quartz however you are comfortable with. I like to smudge them but sometimes I'm not able to, so you can hold it in your dominant hand, envision a white light starting from the inside of the quartz and then bursting out from everywhere of the quartz.
Charge the quartz with what you want it to do (this goes with any quartz) Hold the piece in your right hand and send it your intention. If you want to contact a spirit guide, say or think it. If you want to contact an angel, again, say or think it. If you want to contact a specific person on the other side, say or think it. Give it this charge for a minute or two.
Using it! Hold the crystal in your non-dominant hand. (for me, it's my left)
Meditate. Imagine you are in your happy place and let the guide, angel, specific person visits you there. Feel them there. It may take a few tries before you can hold it in your mind. That's o.k. :-)
When you are done, say your goodbyes until next time.
The Channeller crystal makes this process easier for you and for the spirit. Quartz is an amplifier but the 7 sided face is more in tune with this type of work.