1. Press down the first and third valves.
2. Place your lips in the mouthpiece and blow air through your lips.
3. Adjust your embouchure (the way you shape your lips and mouth) until the note sounds clear and in tune.
You may need to practice this fingering a few times before you can play the G note consistently. Here are a few tips that may help:
* Make sure that you are pressing down on the valves firmly.
* Blow air through your lips evenly and steadily.
* Relax your embouchure and let your lips vibrate freely.
With practice, you will be able to play the G note on the trumpet with ease.