Countless quality training courses have taught them, most every quality book includes them. Flowcharts graphically describe a process. They get everybody on the same page of process knowledge and are invaluable for thinking about processes.
All process work starts with a flowchart.
Do it in public, they are best done with everybody's input. Get a facilitator. Be creative, have fun. I have written a Short Takes on flowcharting for our web site. To read it click here.