Autoused is slightly confused.
2012 silverado garage door opener.
Usually you just hold the button down in your truck until it flashes probably 5 7 seconds then press the button on your garage door opener while still holding down the button in your truck.
Start with the garage door open.
Push and hold the 3 buttons in the truck i think until they flash you might check the owners manual on that.
Programming the car2u is different if you have the newer learn button on your garage opener or the older dip switches.
This system is very similar to the home link system.
Then go push the button on the opener motor and run back to the truck and push and hold the button in the truck that you wnat it to be.
Find your homelink buttons.
Park your car facing your garage and switch on the ignition.
My 2012 came with this as a factory installed option and i ve been using it with my 15 year old garage door opener ever since i bought the truck new in 2012.
The lear product shown in the photo is not homelink they called in universal home remote and lear called it learcar2u.
Ensure that the remote control transmitter has a new battery.
It is likely that they will be located on your rearview mirror your visor or your overhead console.