Tap mode – Tap the beat with rhythmic secondary clicks on the app icon in the status bar (control+click or setup secondary click in system preferences) and the bpm will appear after 4 steady taps. Increasing steady taps lead to higher precision and irregular taps to a reset.
Audio mode – Open the app menu in the status bar and switch to audio mode. Select the input device in the operating systems audio preferences (e.g. microphone or your mixers cue channel using a simple headset adapter to support mixing with vinyl records).