How do I apply these formulas in Excel?

\begin{tabular}{|c|l|} \hline 3. & \begin{tabular}{l} Use the following formula to determine the service charge in cell G4: Service \\ Charge =1.85% (Beginning Balance - Payments - Credits). \end{tabular} \\ \hline 4. & \begin{tabular}{l} Use the following formula to determine the new balance in cell H4: New Balance = \\ (Beginning Balance + Purchases - Payments - Credits + Service Charge). \end{tabular} \\ \hline 5. & Copy the formulas in cells G4 and H4 down through the remaining customers \\ \hline \end{tabular}