>You're meant to raise the clutch to the biting point and apply some accelerator and release the handbrake when you are confident that the engine will prevent the car from moving backwards.
You sit there with the gearbox in neutral and your left foot off the clutch (or in gear and on the clutch if green light imminent) with your right foot on the brake.
In gear, clutch to biting point (which will prevent rolling backward), right foot off the brake and then gradually on the accelerator while you let off the clutch pedal with your left foot.
The handbrake literally never enters into it, and the vehicle never rolls back.
You sit there with the gearbox in neutral and your left foot off the clutch (or in gear and on the clutch if green light imminent) with your right foot on the brake.
In gear, clutch to biting point (which will prevent rolling backward), right foot off the brake and then gradually on the accelerator while you let off the clutch pedal with your left foot.
The handbrake literally never enters into it, and the vehicle never rolls back.