In an empty message box the microphone sits where Send appears: hold it and speak, let go to send, slide up to lock a long one, or slide left to throw it away. Pulling a call screen down minimises it. Blocked and ignored people are listed together in Privacy, where either can be undone, and a direct message has a profile panel beside it. Sign in on your phone is in Kemble Circle too.
Hold to record, and pull a call down
On a phone, Kemble Circle records a voice message while you hold the microphone, and a call screen pulled down is minimised.