I need to put in a commercial oven and don't know what electrical specifications to get for the oven. How do I determine this?

The manufacturer's instructions will tell you. In fact, according to the NEC, you must follow these instructions rather then use the NEC.

That said, the nameplate that is on the oven will give you most of the needed information.

There are several iterations of three phase so it is very important that you know what you have and what you need because you cannot simply convert from one type of three phase to the other.

For your information, we generally strongly suggest that you use a licensed electrician to do this work.

While single phase can be deadly, the voltages and resultant amperage in three phase installations are positively lethal!

Consult the NEC and manufacturers specifications. I would definitely consult also with a qualified electrician to make sure you are wired to specs.