You're about to go to Santorini - congrats! I really enjoyed Santorini and I hope you do as well! Here are some quick tips that should help with your trip planning.
Where can I sleep?
There are a lot of hotels in Santorini and a lot of them have fantastic views of the Mediterranean Sea. There are two main locations in Santorini that you can use to start looking for a place to sleep. One of them is Fira and the other is Oia. The difference between the two is that Oia is by far the prettier of the two. Fira, on the other hand, is in the middle of Santorini and will be easier to get to other locations in Santorini if you choose to do so.
Since we had an Airbnb right in the front row, we were able to order take-out (Greek salad and grilled kebobs, of course) from a nearby Greek restaurant, buy some wine/beer/snacks from the nearby convenience store, and sit down at our own private balcony to view the sunset.
What can I eat?
Since Santorini is a very robust and lively town, there are quite a few choices for eating. Thankfully, the prices are not too expensive so wherever you go, I would suggest trying something new. All of the seafood choices we had were very good. The gyros were also great. And of course, make sure to get your daily veggies with the Greek Salad!
After eating, we would always get some dessert. Yogurt gelatos quickly became our favorite and there are many locations that have some great tasting yogurt gelatos. Side note, why aren't yogurt gelatos available in the US?!
How can I get around?
You could rent a car, 4 wheeler, all-terrain vehicle, etc and drive slowly around the island like a tourist and be responsible for parking.
OR you could ride the super affordable bus that goes all over Santorini. And, in the off-chance that you really need it, order a taxi. The taxis in Santorini are beefed-up minivans that are kind of like a miniature bus.