1. To send a group message in iOS 8 Messages, tap on the new messages icon and enter in the contacts you want to message.
2. Then to give the message a name, tap the Details link and fill in the Group Name. The Details area also will show you where the people are, if they are sharing their location.
3. You can mute notifications in the Details area by sliding on the Do Not Disturb bar. When you’re available to chat again, just slide it off.
4. If you need more people in the conversation tap the plus to add a contact.
5. If you want to remove someone, slide to the right on their name and tap delete.
6. If you want to leave the conversation, scroll to the bottom of the Details area and tap Leave this Conversation.