Follow these steps to learn how to send an SMS message on your Samsung phone.
From the home screen, swipe up to open the menu.
Tap Messages.
Tap the compose symbol.
Tap Recipient and enter a phone number or, tap the plus symbol.
Tap a contact.
Tap Done.
Tap Enter message and enter a message.
Tap the send symbol of the SIM card you want to use.
Your message will be sent.