See visual walkthrough - scroll down the article to the GIF

Steps (mobile):

How to Send a Message:

1. Open the chat that you would like to send a message in
2. At the bottom of the screen tap on the message bar
3. From there you can write as much as you want for your message
4. Once happy with your message press the arrow icon at the bottom right side of the screen
5. You have now successfully sent a message on Coast! 🎉

How to Open a Message:

1. Open the chat that you have received a message from
2. Scroll through the chat group and read the sent messages