If you have the controls on your steering wheel than all you have to do is push the button with the little gas pump logo on it until engine oil life and the percent sign come up on the little screen in the dash.
Then hold down the arrow button (lower right) for 5 or so seconds and it will say oil life reset and it will go back to 100%.
On some Silverado trucks you may have to:
Turn the ignition key to run with the engine off.
Fully press and release the accelerator pedal three times within five seconds.
The change engine oil message will flash for five seconds and the system is now reset.