Unfortunately it is a bit more complex than what you could condense into a single tutorial. The systems are different for every car make, and the complexity increases in newer cars. I am a Nissan Master Tech, so I'm familiar with only my brand. Early systems had a stand alone telematics unit you could just unplug. Newer systems have the telematics integrated with other control systems and networked via CAN (controller area network) with all units in the car. It becomes difficult to kill the telematics without disrupting many other vehicle functions, lighting warning lights. I could probably do this as a custom service, on the brand I am familiar with.