Retirement tax questions

When you go to the business section of TurboTax, you will see a screen that says Let's gather your business info. You need to choose the Self-employed Retirement option on that page.

Later, you will be asked if you want to contribute to a Keough, SEP or SIMPLE plan:

Then you can enter the amount you will contribute or check the Maximize box and you will see the maximum amount you can contribute to your retirement plan.