can you help with showing me the formulas to figure out the columns

Ruiz Co provides the following sales forecast for the next four months, Sales (units) April 510 May 590 June 540 July 630 The company wants to end each month with ending finished goods inventory equal to 20% of next month's forecasted sales. Finished goods inventory on April 1 is 102 units. Prepare a production budget for the months of April, May, and June. June RUIZ CO. Production Budget For April, May, and June April Next month's budgeted sales (units) 590 Ratio of inventory to future sales 20% Budgeted ending inventory (units) 118 Budgeted unit sales for month 510 Required units of available production 528 Budgeted beginning inventory (unita) Units to be produced May 540 20% 100 590 698 630 20% 126 540 666