Finance 250 homework help

Given that a firm had sales of 30,000 last year, gross profit margin (gross profit/sales)=40%, operating profit margin (EBIT/sales)=30%, before tax profit margin(EBT/sales)=20%, and net profit margin(EAT/sale) of 10%, construct the income statement, including a) a cost of goods sold, b) combined operating expenses, and depreciation c)tax liabilities and d) earnings after tax. Use the form (sales-COGS= Gross profit-operating expense&depreciations= EBIT-Interest=EBT-tax=EAT)

I am 10000000% confused right now. Can someone please break this down piece by piece for me. 

Thank you soo much <3