To arrange clips in the Editor panel, you use the Move or Time Selection tools.
Click your recorded clip (or the practice music) to select it. Drag the clip along the timeline so that it begins between 0:20 and 0:30.
Add another file, like music for the intro. Drag it into the timeline, into a different track. Do not place the file directly into another file.
If you put two files in two different tracks, overlapping each other, when you play them back, they will overlap sound.
Now we’re to the fun part: actually editing. There are two ways to edit clips: trimming and splitting. Trimming allows you to trim the beginning and end of a clip. Splitting is more versatile, as it allows you to take out chunks of audio or insert other audio.
Click on the clip to select it
Position the cursor over the left or right edge of the clip. The edge‑dragging icon appears.
Drag clip edges towards the center of the clip. If at the beginning of the trip, it will trim off the beginning of the clip. At the end, it will trim the end of the clip.
The second way to edit clips is to split them. Split audio clips to break them into separate clips that you can independently move or edit.
In the toolbar, select the Razor tool. The default settings for the Razor should be to split only clips you are selected on. Click and hold the Razor tool to select Razor All Clips.
2. In the Editor panel, click where you want the split to occur.
3. Be sure to switch back to the Move tool to be able to move the clips around
4. Alternatively, you can position the time indicator (the blue line) where you want to split, and then choose Clip > Split, or Cmd-K / Ctrl-K.