The basic order flow is something like this:
- Customer places an order, you will be informed via email (make sure you have yourself in the Bcc list in stores > configuration > sales emails > send order email copy to)
- If your payment method has captured the payment, the order will be automatically invoiced. If your payment method has not, before you ship the order go to sales > orders > click the order and then click the invoice button.
- Go to rentals > send rentals when you are ready to ship (or checkout) the rental
- When the rental comes back go to rentals > return rentals and return it