I'm coming up on my third week so it's still somewhat fresh to me. A lot of where you begin can depend on what you already know as well.
I came in having read two BJJ books so I was familiar with the theory and concept and names for positions etc. So we worked on getting my positions locked in tight and how to use space and where to push to break guard etc.
You'll hear position before submission and that's absolutely true, I just want to add safety and control to that.
You need to make sure you're safe as far as where you are in your sparring - are you imposing your game or reacting to his? Are you aware you're in a dangerous position?
Once you are "safe" you need to control your opponent - start setting up for the position(s) you want to attain. This is the start of being one step ahead.
Position - move into whatever positions you have a good number of options from and are comfortable in.
Submission - the fun part
Just listen, learn and enjoy your classes. You can expect to tap (lose) A LOT, it took me I don't know how many rolling sessions to finally use proper technique to tap someone out - but it was just the other day.
Look at jiu-jitsu like you're learning the piano. You need to learn the notes first, then timing, then you'll play a simple song and after years of hard work and determination you'll conduct a symphony.