If arriving in Santorini's Thira town by public bus from the main port (far left), your terminus is the chaotic lower square (center), replete with fast food restaurants and tourist knickknack shops (right) and whose lower road, which you just came in on, leads to other parts of the island such as the black sand beaches and ancient Acrotiri. The upper road ascends to Thira proper and then on to Fira-stefani, Oia and other points.
At this point if you haven't made reservations you'll start looking for accommodations either in a less expensive, non-caldera view establishment or in a caldera view. Whatever your goal, if you are unprepared, you'll have to hoof it and drag your bags around while looking for scarce vacancies which is no fun in the hot sun! No Lie!
Taxis cannot maneuver in the small streets overlooking the caldera or in most of Fira itself. Better hotels have their own special ways of getting your bags to your room like the man you can barely see in the picture far left with a dolly.
Depending on the time of year you may be welcomed with open arms or given regrets. Off season there are plenty of places to stay but don't wait until April to book as you will likely be disappointed.