Adding Invoices to a VAT period is called tagging. Once Invoices are uploaded and processed by AutoEntry they can be tagged to a VAT period.
To tag invoices use the checkbox to the left of the invoice or the master checkbox top left to select the desired invoices to be tagged.
Once selected click on 'Actions' and select TAG from the drop down menu:
A pop up window appears to select both the year and vat period required. The VAT period frequency can be set under company settings.
Click 'Apply Tag'. The selected invoices have now be tagged to that VAT period.