To send a message:
- Open the message app by going to the Home screen and tapping the Messaging app icon.
- Pull down the menu and tap 'New Message'.
- Tap the '?123' icon to add a phone number manually OR
- Tap the + icon to go to your address book and choose a name from the list. You can also pull down the menu to open 'Search for contacts'.
- Tap contacts name and your Jolla shows you the contact details. Choosing the phone number means you'd be sending an SMS, choosing their IM address means you will be sending an IM.
- When you have selected all the contacts you want, scroll back up and tap the glow on the upper right corner. The glow tells how many contacts you have selected.
- Now you can type your message; tap next to the word 'Hi' and start typing.
- When you are done, tap “Send” to send your message.
Video how to use messaging app and more instructions how to use messaging app can be found from here