Cardboard’s SIE export allows you to upload all the payments and receipts collected by Cardboard directly to Fortnox. This tutorial assumes that you have already configured Cardboard for accounting as described here. Navigate to "Accounting" > "Accounting exports" in order to download monthly SIE exports from the buttons labeled with "Fornox (SIE)".

Open the menu hidden behind the name of your company in the top-right corner and select "Import".

Drag-and-drop the .si file downloaded from Cardboard into the section labeled as "Dra och släpp en SIE-fil här eller klicka på Läs in fil uppe till höger." or press the "Läs in fil" button in the top-right corner.

By default, Cardboard exports the purchases against account "1935 - Cardboard SEK konto". This can be changed in the accounting settings of Cardboard or changed during import into Fortnox.

Under the section "Transaktioner" it could make sense to select "Koppla" under "Åtgärd" (1 below) and enter "E" into the "Verserie" field (2 below) in order to connect the payments to "Utbetalningar till leverantörer" (3 below).

Press "Importera" in order to import the transactions into Fortnox.

If the "Merge receipts" feature is not selected, payments will appear like this in Fortnox:

Adding collected receipts exported from Cardboard as vouchers will require you to press into each item and upload the matching receipt. If you want to save time, you can select the "merge receipt" button in Cardboard's accounting settings and re-export the SIE file. All transactions will then be grouped into a single item in Fortnox like this:

All purchases are grouped into a single item, to which you can attach the merged receipt available from the "Merged receipt" button besides the button you downloaded the SIE file from.

The KS and PR, kostnadsställe and project respectively, can be populated with correct values by entering values for "Department number" and "Project number" in Cardboard's accounting settings.