Blender knife project

Blender's Knife Project tool is very useful.
I like to remember it as 'Knife' 'Project' as in 'my project'.
This way, I can remember the sequence as follows:
Select the cutter or 'Knife'. It has to be a non-manifold object in front of object to be cut.
Shift + Select your 'project' object.
Tab into edit mode, hit Knife Project in the tool panel under basic tab. Only shown in 'Edit' mode.
Now you can delete the cut faces if you desire.

Good advice....