This document provides instructions for plotting radar targets over a 6 minute interval to determine course, speed, closest point of approach (CPA), and time to CPA (TCPA) of other vessels. It outlines the steps to mark initial bearing and range, draw target movement line, transfer own vessel movement, calculate distances traveled, and determine other vessel's course, speed, CPA and TCPA. It concludes that in this example, if no course or speed changes are made, there will be a collision at a CPA of 0.0 nautical miles at 12:09:48, and that the observer is the give-way vessel in a crossing situation.