Where do I put in the information for Simple IRA contributions?

That depends on your work situation (self-employed or employee). 

If you are self-employed, you'll enter your SIMPLE IRA contributions under Business Income and Expenses > Less Common Business Situations > Self-Employed Retirement. 

If you are an employee, contributions to your SIMPLE IRA are reported on your W-2 in Box 12 with code S. You'll only need to enter this information in the W-2 section of TurboTax. Please see the FAQ below for instructions.