If you create a project without adjusting the target group or reporting period, the campaign is set to have a wide, undefined target group, and a reporting period stretching from the last day of the campaign and 12 weeks back.
If you wish to change target group or reporting period, you can do so in the top right corner, below the filter button.
To change your target group, just click the button shown below, and then click "edit". Now change the attributes of your target group and click "Save" in the upper right corner.
If you want to change the report period, just click the button next to the target group button. Then click "edit", and change the report period in the new window that will appear. You are only able to select full weeks from Monday to Sunday in the system.
After changing the report period, remember to press "Save" in the upper right corner.
Both changes in target group and in report period will be updated immediately. Please note that it is only possible to review a period of 12 weeks at a time.