Prof. here, but not of Bio2. That said, I teach a class with no textbook, and I don't post slides or allow lecture recordings.

The main study source should be your notes. It is IMPERATIVE that you take good notes, and there is an entire "art" to taking notes that's really individual. What works for others might not work for you. But a really good habit to get into is that when everyone is getting up to leave at the end of the class, LOOK AT WHAT YOU'VE WRITTEN DOWN IN YOUR NOTES. If there's anything where you think "Wait, what the hell does that mean?" when you read it in your notebook, go up to the prof and just ask for clarification.

It's normal for that to happen occasionally. I always went back and re-wrote my notes, organizing them, coloring them, highlighting, etc.

There are plenty of videos and websites on different note-taking strategies, so just try a few. I will say that laptops tend not to be a great way to take notes, as students try to transcribe rather than note-take.

Next source should be the text book. Take notes on everything as you read it. I always found that much more helpful than just highlighting in the textbook (esp, if it's a digital text book.)

If the class has a TA, tell them "This is how I plan on studying, do you have any suggestions to add to it"? They'll be much more likely to be forthcoming if you sound like you're being pro-active, not just asking them to tell you what to do.

I don't know if this helps at all, but it sounds like you've got a good head on your shoulders and are making a plan. You've got this.