What are the rules I need to follow to open a business in the USA?

[San]

As a UK citizen residing in the US for 15 years, I plan to establish a food business. Please provide a systematic outline of the following:

1. What are the core legal requirements for registering a foreign-owned business in the US?
2. What specific documentation and procedural steps, including EIN acquisition, are required for non-US residents opening a business?