Hello there!
You can add the time worked by enabling the option Input worktime for the desired Ticket Types under Configuration\Ticket Content. This option allows your Helpdesk Agents to fill in the work time per note themselves. Once your agents have added a note they can input the time worked by pressing the hammer icon on the note.
This data is then stored in the database table in htblnotes.timeworked which is used in the report that you are referring to. Keep in mind, however, that this field stores the data on a note per note basis, so you will have to use the 'Sum' expression to count these notes for one ticket if you would want to use this in a report.
Additionally, the Time worked on (States) as shown on your tickets is dynamically calculated based on how long the ticket was in states which have been configured to count as work. As this information is dynamically calculated, there is no database field which holds these values.

