Takes about 3 minutes. You only do this once.
1
Go to console.cloud.google.com → Create a new project (or select existing).
2
Search for "Google Sheets API" → Click it → Click Enable.
3
Go to APIs & Services → Credentials → + Create Credentials → API Key. Copy the key (starts with AIzaSy...).
4
(Recommended) Click the key → Under "API restrictions", restrict it to Google Sheets API only.
5
Your Spreadsheet ID is in the URL:
docs.google.com/spreadsheets/d/THIS-PART/edit
6
Share the sheet: Anyone with the link → Viewer, OR use an API key from the same Google account that owns the sheet.
✓
Required columns per tab: Campaign Name · Affiliate · PIC · Cost · Leads · FTD. Date in column A recommended.