Re: I so confuus...

When you go to your friends list, you'll notice an icon that looks like a chat bubble. You can tap it and type in your message. They can even recieve the message during matches.

Sadly, the players must be online in order for you to send them a message and you can't be in a match yourself when sending.

If you want to have a conversation, you must both be online and out of a match to do so.

I hope this helps. It's a very limited chat system, but it is there. Most of my friends i just chat with on whatsapp.