Get your taxes done using TurboTax

I didn't receive a 1099-G form and so I looked up the total refund received from a previous year's tax forms.  However on the TT page, it asks for "Total of all your payments and withholding."  Where would I find this on either a W-2 or on previous year tax form (what specific line item)?  I switched employers mid-year, and so I wonder if I have to add certain amounts.  I would appreciate the advice.