You must prepare a corporate tax return first. As part of that corporate tax return you must issue a W-2 to yourself as employee and pay reasonable compensation. Then the remaining profits will be taxed without SE tax.
Since Turbotax business is only available for PC, you will either need to buy a cheap PC for the business, or borrow a PC, or use one of the software solutions for installing a virtual PC on your Mac.
After you have the W-2 and the K-1, start your personal tax return over from scratch. (It should not have a schedule C unless you also have another unincorporated small business.)
