The first thing you need to do to become an official LLC is file your articles of organization in the state where you will be doing business.

As I explain in more detail at http://www.llcwizard.com/articles-of-organization-2, this is the first step in fulfilling the needed formalities to show that your company is a separate entity from yourself.  Everything you submit to the state through these forms will be public information, so provide only what they ask.

The government granted limited liability to encourage people to start businesses by limiting their exposure to liabilities incurred by the company.  But you only get the liability protection if the state recognizes you as a company, so filing the articles of organization is a first and essential step.