The position you want to be in at the catch is with your shins vertical (perpendicular to the floor) with knees stacked over the ankles. Your heels may or may not come up in this position (this is based on your ankle flexibility) so either is fine!
Here are a few resources below developed by our Athletes and Coaches to provide good technique pointers that are beneficial for all of our users:
We would also recommend looking into booking a session with our Personal Coaches for more individualized coaching if that would be of interest to you! Here are a few links below with more information on this service: