The Guide is one way of solving the issue of a viewer getting “lost” in the 360 video and missing the important part of the video.
Here are the instructions Facebook posted for using the Guide:
• When you upload your video to Facebook, check “This video was recorded in 360° format”
• Head to the new “360 Controls” tab
• Check the box that says “Enable Guide”
• Play through your video to identify the points of interest that you don’t want your followers to miss
• To add a point of interest, select “+ Add Point” when the video is paused, and that point of interest will be added to Guide.
Here is the official announcement of the Guide and the Heatmap tools.