First, if you are using a machine in the lab and Audacity doesn’t seem to work right — it could be the machine. Try another!
- The “time shift” tool is what allows you to change relative position of tracks (so that they can “stairstep”). See this toolbar description page and this one-minute podcast tutorial.
- To reduce sound or increase sound, select the track (or parts of a track) — Effect -> Amplify
- Audacity support from Gov’t of Oz
- Audacity 1.2 online manual
- Audacity tutorials