This script works exclusively with this https://docs.google.com/spreadsheets/d/1PRr_s6Nsus3ATx9hHl8LJOjRCvZpQ5IyXRHnBzwOAUs/edit?usp=sharing template. Basic purpose of the script is to save the selection of material for the customer and generate the proposal.

Create a copy of the template for each client.
Select Roofing type, Shingle or Metal for your client.
Select the appropriate package Silver, Gold or Platinum. Its the cell L3.
Select the required material and labor cost from the tables below.
If you are unable to complete the selection then you can save your work by selecting "Yes" from the drop down that says "Save". Its the cell L5.
If you are done then Create the order by clicking "Create Order" from the appropriate menu item inside  "MET Script 3" which is in the Add-ons menu.
Go to the "Pdf Generator" Sheet and select the required Proposal Sheets. Fill in the name of the Proposal and clients email address fields.
Click "Generate Pdf" which is inside the MET Script 3 menu item which is under Add-ons menu.