Add your **per‑dwelling costs (ex GST)**, tick **Supplying** where you provide the item, and add **Notes** where helpful.
Submission posts JSON to your webhook. Replace `WEBHOOK_URL` below before use.
Deploy a Google Apps Script Web App bound to your sheet, then paste its URL into WEBHOOK_URL below. **Crucially, the Apps Script must include a `doOptions()` function to handle the CORS preflight request**.