Once you have been invited and registered as a user in the Salary employee app, you can register hours under the - "Tidsregistrering" tab at the bottom of the app. You must select the date and number of hours, as well as the hourly rate you will need.
You can also add a note to your employer. Once the hours are registered, your employer must approve the hours for them to be included in the salary. So remember to register them well in advance.