When you want to add a new contact:
1. Open the People app
2. From the pulley menu above, choose "Add contact"
3. Fill-in all the fields you want. You can edit these again later if needed.
4. Save your new contact by swiping left, or by tapping "Accept" in the top right corner.
5. You can now see the address card you created. If you want, you can press the (+) icon to assign a profile picture to your contact from the Gallery.
Tip: If you want to add several contacts for example from another device to your Jolla, please refer to these articles.