Step 1: did you receive money? That is income. Step 2: if you incurred expenses in making that money, and that money is not a wage/salary paid by a business, deduct those expenses from the income in Step 1. Otherwise, deduct nothing. Step 3: look at the tax table for the amount at the end of Step 2 to see what the tax you owe is.

It only gets complicated if you want it to be complicated, such as if you're trying to maximize potential deductions or minimize taxable income by exploiting loopholes or special provisions.