To set up a function in Excel that copies values greater than zero from one column while leaving other cells empty, use the IF statement. The formula to achieve this is =IF(A1>0,A1,""). This formula checks if the value in cell A1 is greater than zero; if true, it copies the value, and if false, it returns an empty string. This method effectively filters out non-positive values, ensuring that only positive numbers are displayed in the target cells. For additional guidance on using IF statements in Excel, resources like Excel Trick provide further insights and examples.