And so was I when I first read about it! I just looked for random YouTube videos that walked you through exercises of how to get rid of your neck hump and bad posture. Most were a mix of exercises that had you basically do the opposite, like lay on your back with a rolled up towel under your shoulders and push your head on the ground, or some general posture exercises like pushing your shoulders back and tense up your neck in a straight position.
I'd recommend to look those up for yourself, as I am terrible at explaining and not a professional, haha. I can't give any specific recommendations as I simply can't find them anymore. But trying to look for them made me realize again just how many there are ...
I can give another recommendation; while you may feel the effects in your neck, it can start well further down from your feet up. Do calf/thigh stretches, tilt your hips "back" (tense your buttocks, do kettlebell swings, dead lifts, squats), shoulder exercises (rows), etc.
You can often tell when people have a desk posture from their hips being tilted backwards and/or pot bellies (even if they're not overweight).
