The Selection Tool is used to select audio. You can click in a track to position the cursor to play from, or click and drag to select a range of audio.
The Envelope Tool gives you detailed control over how tracks fade in and out, right in the main track window. When the envelope tool is selected, the amplitude envelope of each track is highlighted in a green line, with control points at the beginning and end of each track. To change a control point, click it and drag it to a new position. To add a new point, click anywhere in the track where there is not already a control point. To remove a point, click on it and drag it outside of the track until it disappears, then release.
The Time Shift Tool allows you to change the relative positioning of tracks relative to one another in time. To use this tool, simply click in a track and drag it to the left or right. To align two tracks together or reset their time shift back to zero, use the Align Tracks Together or Align with Zero commands.
The Zoom Tool allows you to zoom in or out of a specific part of the audio.
The Draw Tool enables you to draw in to the actual waveforms. This is especially useful to eliminate small pops and clicks from material. For instance ALT + click smoothes a area of audio.