Preparing and getting the final result. If you don't understand the process of what the technician is doing, then you aren't going to be able to explain to your lab tech how to fix something if it's not right.
The important part of your prep is the control of the tissues. It is by far the most important step. If you can't stop the bleeding, if you can't get crisp margins in your prep, then stop, place a temporary and come back another day. It is better to take your time rather than pushing through with something that won't achieve a great result.