Discussion with the whole team :
To start a discussion with your whole team (public messages), you can go to the forum of an event: match, training, tournament, or other.
You can access it directly from the page of the event concerned (on the site and on the Android app - soon on the Iphone app), or directly from the homepage of the site, where all discussions of the team are grouped together.
Discussion with some members only :
To start a discussion with some members of your team ('private' messages), go to the 'Messages' tab > 'New thread' on the left.
You will then have to fill in the "Choose or add a recipient" field and add the person(s) to whom you wish to send the message via internal messaging (thus in private messages).