What power do I need and how is it wired

I don't know where to start.

What kind of fixture?
Where is it going?
What is the draw? Wattage?

You cannot have a 277V lighting fixture in a home, not that 277V would even be available.

Your question is just so vague no one will be able to help you until you give us more detail.

My gut reaction is anyone asking such a question in such a way should not even begin to consider working on anything like this.

You need 277 VAC, typically found in commercial locations and paired with 440VAC.. This is not 240VAC. Don't mess with 277 if you don't know how to wire it. What are you trying to accomplish?

I don't know where to start.

What kind of fixture?
Where is it going?
What is the draw? Wattage?

You cannot have a 277V lighting fixture in a home, not that 277V would even be available.

Your question is just so vague no one will be able to help you until you give us more detail.

My gut reaction is anyone asking such a question in such a way should not even begin to consider working on anything like this.

Talk about close timing!