Step 1 - Come up with a name for your LLC and make sure no one else is using it in your state. You can search the name online.
Step 2 - Get a federal EIN tax number (free - online):
https://sa1.www4.irs.gov/modiein/individual/index.jsp
Step 3 - Apply for LLC with your secretary of state ($130 in Wisconsin - online):
https://www.wdfi.org/apps/CorpFormation/directions.aspx?type=12
You can get all of this done in about an hour once you get a cleared name. Pretty easy…