Jack,
As was mentioned earlier, you really should get a copy of Paul's book.
In the meantime, this is how Liquid works; First, the timeline is in one of two modes, Insert editing and Overwrite editing. If you look between the source and master viewers, you'll see a large downward arrow. This arrow will be either yellow or red. Yellow means you're in Insert mode. Red is for Overwrite mode. When you're in insert mode, everything likes to snap to the left (so if you take a clip and drag it to the right, it'll snap back to the left when you let go). Deleting part of a clip in Insert mode causes clips to the right to snap to the left. Overwrite mode lets you overwrite the timeline at any position. Drag a clip and it'll stay where it's dropped. Clicking on the arrow will toggle the mode.
Second, when you drop clips on the timeline, by default the audio is linked to the video. And depending on how you put the clips on the timeline, you may not even see a separate audio track.
If you don't see a separate audio track, right-click the track in the timeline and choose Disband. You'll now see separate audio and video tracks. If the tracks are linked (and they probably are), then dragging the handle on the video track will also drag the handles on the audio track(s). To manipulate them separately (which is what you want), right-click on the track in the timeline and choose Unlink Items. Now the audio is separate from the video, and you can drag the handles on one without affecting the other.
Hope this helps.