Can you help me create a new form pls

You can use Form Calculation widget for your calculations.

Please check this guide https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget

"Now he wants sides finished" You can have Single Choice properties for Yes/No and assign a calculation value if the user selects Yes.
https://www.jotform.com/help/301-How-to-Assign-Calculation-Value

Door handle/accessories can be in a Short Text Entry if they have the option of how many they can buy

Unfortunately I am not able to see the whole calculation of the Excel Spreadsheet to see the prices under those column.