Not a video or even a regular tutorial but I did a quick walkthrough with screenshots that might get you started.
That's pretty old and incomplete but still useful. To do anything useful, you'll need to go through some basic steps.
1)Start by first creating a Path project.
2)click on the tool table button and add at least one tool.
3)Load the tool
4)Now add an operation like a profile or a pocket. The different operations will require you to select appropriate geometry. ie profile wants a face selected but if you're using libarea to profile, you select a collection of edges. This is really rough and it's the area that needs development help.
if all goes well, you'll see the tool path lines added to the view. Adjust the properties of the operations for offsets, step-down, etc. The libarea profile is probably the most useful at this point.
5) If you're able to get the tool path lines to look the way you want, you can then post-process to generate gcode. Gcode can also be customized by modifying or writing your own post processor script.
So far I've only been able to make very simple things with profile operations only. Still, you might be able to glean some useful info from looking at a project: http://sliptonic.com/dogfooding-with-freecad-path/