Chunks of audio can be marked using colours. These can be selected from the Audio Side Bar:
The boundary line below each group can be dragged to reveal or hide colours.
To colour a chunk of audio place the cursor in the chunk (if the cursor is not already there) and then select the colour.
To colour a chunk while in the Audio pane; choose the colour from the side bar, or use the simplified shortcuts; number keys 1-5 (0 resets it to the default).
To colour a chunk from the other panes (the chunk that will be coloured is wherever the Audio Pane cursor is); change the Side bar to the Audio Sidebar using the tabs along the top and choose the colour. Or use the complex shortcut; CMD Alt + Number keys 1-5 (0 resets it to the default).
Chunks can be returned to the default colour using the default audio colour button on the Side Bar or (CMD Alt) 0.
You can edit the Colour Key; allowing you to change the colours and text of each option. See Changing Coloursfor more information.
While recording live, you can also use Continuous Colouring; This will colour successive audio chunks with the selected colour, as they are created. Continuous Colouring is active by default, you can turn it off in the Audio Side bar: