As a general guide, ask questions like your life depends on it. As an intern, no one expects you to know what to do nor how to do it, at least not right off the bat. It is your duty to make the effort to reach both of those though, and asking questions is by far the best tool to do that.
When I occasionally interface with interns, questions are my number one metric. If someone asks a lot of questions and at least some of them are in the right direction, they're already a keeper in my book. If the intern doesn't ask any questions I won't know how to help them on either and that's a bad sign.
Best of luck and don't forget to have fun.
Yes and no, questions are important but do try to collect a few questions to one sitting. In the said notepad collect questions and when you feel it's right go ahead and ask them.
But before that try to answer some of them yourself, and check whether they were answered somewhere else.
One of the keys here is ask ONCE, if you need to ask a second time, then you are wasting my time. Hint: if you need to I recommend asking someone else the second time, and then do not forget the answer.
1) whom do I report to? - corollary who do I NOT report to? yeah some people try to inject their needs when they have no authority to.
2) what are the required weekly items: - meetings, emails, schedules, reports
3) security expectations - badges etc
4) who to contact if you are too ill to come in
5) report times - when are you expected in? How flexible? when is lunch? How long is lunch? Where is lunch? Do they serve beer? ...
6) how to contact IT help desk
7) where is the emergency exit - yeah I am serious about that
8) how do you record your daily time
9) how do you do your job? Is it routine, or unique projects?
10) expect to be assigned a mentor, make sure you have their contact info - if possible both their work and personnel.
11) when are you paid? How are you paid? Some jobs require you to have direct deposit.
12) (day 3 or so) what extra benefits are there - large companies often have deals with entertainment groups e.g. Disney discount tickets available at such and such.
13) look for organized clubs at work - this can be a great source of building a social network to convert that internship into a job - as long as the others are employees and not just interns.
Like others mentioned, you need a notebook - write quickly as you will get a LOT of information the first day. That night convert it to a soft document - review for unclear answers or items to ask about the next day.
Show up early the first day - coat and tie - expect them to laugh and say 'oh we are not so formal around here, just where business casual'. Still wear a coat and tie, first impressions are important and you cannot re do the first impression. And yeah I would think less of you if you did not show up on the first day in coat and tie, even when the standard is tshirt and jeans.
Bring a book with you, one that makes you look smart for reading it. Preferably be to chapter 4 or more, anything else looks like a prop. If you get there too early, which is MUCH better than 5 seconds late, then you can read your book. Popping open the book when you have down time, which is VERY common the first week, makes you look industrious, and reaffirms that hiring you was a smart thing to do.
I wouldn’t go as far as jacket and tie on day one, but definitely arrive dressed a full level more formally than you will most days. Button down and chinos rather than t-shirt and jeans. Blazer rather than polo shirt. Etc.