The PDU1 form is to be used when you apply for unemployment benefits from another member state within the EU-/EEA or Switzerland. The form is needed to merge the periods of employment completed in Sweden with periods of employment/insurance in the member state that you are applying for benefits from. The PDU1 form can also be used if you have been living in another member state while being employed in Sweden.
Therefore the form need to contain information regarding the periods that you wish to combine.