Well, it's just a trick you need to get the feeling for. Start one foot on the break, and other on the clutch. Let clutch go halfway, without stalling the car, and quickly move your right foot from brake to gas. Press on gas pedal, while releasing clutch. If you do it right, the car starts driving forward, even on a upwards hill. It takes practice, and every car feels different.
Perez, Leclerc & Russell need to stop crashing into cars/walls. They all threw it away. I feel bad for Albon though, he did everything right, bad luck.