Adding a Sepia effect could not be easier. Simply open the photo, and go to Menu > Effects > Camera > Sepia Toning. Make the adjustments you are after in the Sepia Toning Dialog. But I would always recommend first creating a duplicate object of your photo in the Object Manager Docker. Select the duplicate, and repeat the steps. This way, the Sepia Toning will only be applied to the duplicate photo object.
Tip provided by Stefan Lindblad, CorelDRAW Master, Illustrator, Graphic Designer & Artist.
Don't forget once you have a Sepia you can convert to LAB and really have a grand old time editing the color!! You can also use RGB curves to your liking.