First of all congrats on pursuing the snatch its a lift that too many people stay away from because of its complexity. As someone who just started OLing 4 months ago I understand your troubles at this point. At the beginning my form was literally SHIT, so
You definitely want to stick to lower weights and progress from there, go from the hang for a while, then eventually progress down to going from below the knees. The snatch IS ONE SINGLE, FLUID MOVEMENT. Also as my coach told me at the beginning, try to make it a fluent movement, DONT RIP THE SHIT OUT OF THE BAR, the movement should look smooth.
Doing it with a bar is much different than with dumbbells, and requires much better form. You shouldnt be able to snatch as much as you clean and jerk/press.
I would suggest that you start by just doing your work from the hang with the bar at first and practice that way. In the meantime work on lots of overhead squatting and drop snatches. These will help you get a better feel for the movement, and will also help you keep the bar up there in the catch phase, and they will improve you bottom position flexibility for later.
Just take it slow, avoid the tendecy to sacrifice form for weight with the snatch or you will stall very quickly.
Hope that helps. If you need anymore help just shoot me a PM. Good Luck.