First thing I would do is come up with a catchy name for your business. Once you have done this you can goto your state's licensing website to apply for a corporation or LLC etc. You should be able to Google your state corporation registration to do this. You can pick your name online and then pay the fee usually around 100.00 and within a day or two you will be official. I would suggest hiring an accountant to help you with this and get the proper corporate structure setup.
Once you have your corporation registered then you need to goto the irs.gov website and apply for an EIN (Employer Tax Identification Number) Contact the county clerks office you live in and ask them if you will need a county occupational tax license in addition to the city. You will need to get both of these.
After you have done this, you can get your bank account setup in your business name. Feel free to contact me via email email@example.com and I will answer any questions I can to help you out. Check out our website below which links to 2 of my computer stores for ideas.
Check us out at Computer Repair in Lakeland FL and Brandon FL