A - Channel selection buttons.
B - Loop start indicator. Click and drag to move it. You can also use "Set Loop" in the "Edit" menu.
C - Playhead indicator. Clicking anywhere on the ruler will move the playhead, if the sound is playing, it will stop the waveform display from auto-scrolling.
D - Ruler.
E - Loop end indicator. Click and drag to move it. You can also use "Set Loop" in the "Edit" menu.
F - Vertical zoom controls.
G - Horizontal cursor position and sound length.
H - Horizontal zoom controls. You can also use the up/down arrows.
I - Selection range.
J - Loop on/off button and loop range.
K - Transport controls. Stop, Play, Shuttle and Record.
The Stop button will stop the sound from playing or recording. If it's already stopped, it will move the playhead to the beginning of the sound. Hitting the space bar will also stop playing or recording.
The Play button plays the song. You can also hit the space bar.
The Shuttle will rewind or fast forward the sound. Click and drag to the left or right. If you hold down the option key, it will play the sound slower instead of faster.
The Record button starts recording a sound.
L - Playhead position.
M - Waveform display and editing area. This is where you select part of the sound to edit it or add effects. Note: to adjust the selection, shift-click the waveform. To toggle the channel selection, command-click the waveform. If the sound is playing, clicking on the waveform display will stop it from auto-scrolling.
N - Level meters. When playing it shows the output level. When recording it shows the input level. The clip indicators show when the level is above 0 dB.