Creating a partnership business in Las Vegas

Hello,

An old friend of mine who's an investor in Las Vegas suggested that we partner up on a deal together. I want to know what steps we need to take prior to working together. I am in California so would it be better to set-up the LLC in Vegas? We will also be setting up a Joint business account under the name of the LLC. Additionally, is a partnership agreement also something we should have?

Thanks,

Armand