Self-employment proof of income

Hello, I need to report side income received from private art lessons. All payments were by personal checks. There was no 1099-MISC and there were no expenses to deduct, hence I didn't see a need to upgrade to Turbotax Self Employed. In Turbotax Deluxe, how do I prove to the IRS that my reported income is correct? I don't see any option to upload a spreadsheet or bank deposit records. Thank you.