To create a new message, tap the message icon; In the address box, enter the name(s) or username(s) of who you wish to send a message to. Group messages can include up to 50 people.

To send a DM on Twitter, use the envelope-shaped Message icon in the app or website. You usually have to follow someone before you can send a DM.

With every app change, learning new icons and tools is an adjustment period. The Google Messages app is going through that now, changing up what a sent, delivered, and read message icon looks like.