CONFIRM, you will need a 50 amp, 240 volt, GFCI protected ("Square D" suggested). The NEC code and your electrician have the best answers to your questions.
Regarding your statement, "We know absolutely zero about setting up and maintaining a spa." Rely on your professional resources. Everybody here knows what you need, IF they have the specs and installation info for YOUR spa, but you can not sue them for something wrong.
Let me put you at ease, the Hot Tub has been manufactured by a reliable, well known manufacturer that is fully liable for any product deficiencies. They have provided detailed information to you, and it is imperative that you properly inform, or provide your electrician with the information provided. The Hot Tub as it is presently, does not pose a threat or danger to your family, IF your ELECTRICIAN knows what he's doing.
IF you have questions regarding hook up, or better, if your electrician has questions, provide the dealers phone number, and/or the manufacturers number to him, and take two asprin and relax, your just excited and want everything to be absolutely perfect. That will happen as things fall into place.
Congratulations on your choice, get it wired, then filled and your ready to soak. Your next dilema will be "proper" water chemistry. You should consult with your dealer, as you do have an ozone sanitizer on your unit. He is the best source of information. IF THAT relationship breaks down, you will find all of the answers here, BUT the subject is deep, and the varing opinions could conflict, as there are many.