The navigator window contains a small map of the timeline for your entire project. Its main purpose is to allow you to move to specific parts of your timeline quickly, which can be done simply by clicking on it.
Chromakeyer is basically a device which replaces everything of one particular colour with parts of another picture. This technique is known to most people, although normally they refer to it as "green screening" or something similar.
This tutorial demonstrates how to add a "Bug" to the corner of a video. The tutorial also explains how to import 3d animation from a 3rd party application (Ulead 3D) to be used as an "animated bug"
