Hi there. I'd recommend you watch these videos: http://www.californiastrength.com/vi...-weightlifting
click on the "snatch" and "clean" icons and they give you a really good tutorial for learning the lifts
. Try and do what they tell you.
With regards to your video and your snatch:
Your start position is pretty decent, maybe just need to raise your hips a little bit. It's important to keep your shoulders directly over the bar.
In your first pull (floor to knee) you need to raise your hips and shoulders at the same rate. driving through your heels.
second pull, you need to extend those legs whilst keeping your shoulders over the bar. You do this, but you need to do it more. Also, keep that bar close to your thighs! essential. You pull with your arms when the bar is about halfway up your thighs, you need to keep those arms relaxed (think of them as cables) and let your body do the work.
to stop yourself from jumping forward try thinking about jumping backwards just a couple of inches. Hopefully that'll balance you out.
your catching position is really good! Because it's such an unnatural position it will feel uncomfortable, but keep practicing and it'll become like second nature. Do some overhead squats to help you get used to that position.
In general, watch those videos, keep the bar close and keep lifting!
I hope that's not too much information and it's helpful
EDIT: P.s. practice with just about 30 kg, should be a good weight for you to practice with