You can add a new transaction by clicking the button.
From here you can select the date of the transaction, the currency of it, the type of transaction (sales invoice, sales credit, sales receipt, sales refund, write off and write back), you can then select the product from the drop down.
Finally you can select the year, period and payment method. After this you can select the company, contact and the order.
After this you can add references and a due date.
Once you are happy with the transaction details click the button.