Please can you let me know how to setup open orders export only once, every hour. So if the export runs at 10am then at 11am I only want open orders that have come in since that last export.
This can be achieved via setting up a scheduled export routine, that would be exporting the data with a predefined interval on a regular basis.
The link below covers the topic of scheduled exports in more details:
The scheduling part I understand but will this export all open orders or just the ones that have not been exported?
By default it will export all orders, however there are filters that you could use in order to export only new orders.
In the column mapping screen, you will see a filter icon next to some of the columns.
Received date (when order was made on the channel) and Created date (when it was downloaded to Linnworks) will have an All since last export option:
Bear in mind that orders can be made while an export is running so when using these filters there is a slight chance for an order to be skipped if that happens. For instance when using the Received date filter order is created on the channel on 12:43:15 and an export runs on 12:43:36. Since the order is not yet downloaded to Linnworks, there is no way to export it, however the next export will check for orders between 12:43:36 and current time so will not include such an order either as the received date is before 12:43:36 when the last export was run.
Hence using the Created date filter may be a better option.