1. Pull sales from each channel. Shopify, Amazon Seller Central, retail partner portals, wholesale EDI.
2. Standardize the schema. Each channel uses different field names for SKU, quantity, gross sales, fees, returns. The flow maps them all into a single common schema.
3. Stack them into one table. One row per order line, one column for channel.
4. Roll up by month and channel. Revenue, units, AOV, returns rate at whatever granularity you need.
5. Output the report. Full table for the record, plus a pivot for finance and a Slack message with the weekly headline.