Hey Manuel -
First thing is to get your grip a little more solid. Get your hands and wrists in a position so your wrists don't get bent back in the way down. You're losing your leverage over the bar and that's causing some down-the-line issues.
Next, walk out into a slightly wider stance. About 2 inches more total distance between your heels, and turn your toes out a little more. THEN shove your knees out to the sides, HARD, immediately upon beginning your descent.
Finally, you need to stay in your hips. Drive your hips up, first and hard, out of the hole and keep driving them. Don't switch to lifting your chest partway up.