asking questions + paying attention: It will often start with no one explaining you anything. If you don't ask questions, you won't learn. So start making notes of things you don't understand, and then LATER when your manager has time asking them. And then take notes on the answers too. People like explaining things, but not multiple times.
being curious: take an interest in how the work gets done, what people other than you do every day, how what your group does plays into the larger picture, etc. it'll help you do your job better.
being preemptive: looking for work and picking it up instead of being idle and waiting to be assigned because no one gave you anything to do. Assigning work to an intern can be tricky because people feel it has to be a not too easy not too hard goldilocks. Show that you're made of sturdier stuff.
Overall, interns are not infrequently more work for employees than they're "worth". Don't feel self conscious about this at first though (they knew what they were getting into) but make it clear and obvious that you're doing your best to learn the ropes and to become net positive helpful before the end of the whole thing. You'll gain more respect by being humble and being seen doing the work than being boastful about your skills. That'll also mean you might get an offer to come back as a full time employee.
As long as you're roughly following these, there's no need to be stressed. And you'll ensure that you're maximizing your experience, which is worth more in the long term than whatever measly pay they might be providing, because it'll help you get your next gig.
I'm sure you'll do great! Good luck!
