I receive a notification when starting sales orders that the administration is not complete (down payment item is not set up). What can be done about this?

To be able to use the sales orders module, a number of settings need to be specified. One of them is the setting for the article number to be used for registering down payments.

First, check if a down payment article already exists. This article should be of type 'No revenue' and should be sold at 0% VAT. Then go to Settings -> Financial, and enter the article number of the down payment article to be used in 'Down payment article'.