Revised:
Build a cart
Add the chosen quantities from shared catalogues to the cart. Products belong to their selling company, so a mixed cart becomes separate orders per seller. Review the seller, price level, currency and quantities before sending.
Wait for confirmation
The request lets the seller review availability and commercial terms, including shipping. A submitted request is not evidence that the goods were dispatched or paid. Follow its status in My orders and use the confirmed terms when arranging fulfilment.
Recover safely from errors
A network interruption can leave the outcome temporarily uncertain. Use the existing request status and retry guidance rather than creating several identical orders. During warehouse preparation, check the product identity and quantities before recording the stock movement.