The first pull of the clean and snatch is from the ground to the top of the knee. If this pull isn’t done correctly, it can set the lifter up for all sorts of problems in the rest of the lift.
A common problem for new lifters is the hips coming up before the shoulders. The back angle should remain the same throughout the entire first pull, until the bar passes the knees.
The halting snatch (or clean) deadlift is a great tool to get this movement corrected. It is executed by pulling to above the knee or mid-thigh and pausing for 2-5 seconds. During this movement, the focus should be on maintaining the back angle and getting the knees back and out of the way.
Practice this drill to set yourself up nicely for the 2nd, more aggressive pull.