The iBook trackpad button is located just below the trackpad, as shown in the graphic below.
Figure 2, Trackpad control panel
Figure 1, Location of trackpad button
To enable trackpad clicking and dragging, follow these steps:
1. Open the Trackpad control panel.
2. Click in the checkbox marked Clicking, as shown in the graphic below. This will make the Dragging and Drag lock check boxes active. Check them if you desire those features.
3. Close the Trackpad control panel.
Figure 2, Trackpad control panel