Let me exapand on tst's comments.
Flow charts are seldom used with LabVIEW.
LabVIEW's programing consturcts (For Loop, While Loop, Sequence structure, etc) are composed of multiple Flow Diagram elements.
Asking for a flow diagram of a LV diagram is like asking for the illustrated parts break down of a automobile when you want to learn how to drive it. What you really would need in that case would be the user manual.
The closest thing to an "Owners Manual" of a LV diagram is the VI documentation that tst mentioned.
Another possiblity would be the "State Diagram" if the code was developed from a State Diagram.
Aside from two examples, I have never seen any code from NI that used a SD.
Now back to helping you....
The details of the diagram operators used in the VI you want to understand can be learned by reading the help text for the operators themselves.
To better understand how they are bieng used together, I suggest using "Execution Highlighting" (light buld mode).
Watch the code in execution highlighting. You can single step if the diagram is moving too fast. If you want to track what is happening to the data as it executes, probe the wires that are involved in the action.
Once you have become familiar with the diagram objects and the dat flow paradym, you will find that LV diagrams (when properly written) are in themselves an illustration of what they do.
In many regards they are superior to flow diagrams because it is easier "ingore the the trees to appreciate the forest".
Ben
Side note:
Durring kick-off meetings my boss will get up and take a break (sorta like a band before a drum solo starts) when he hears me start my lecture on how flow diagrams are not that useful in LV, blah, blah, blah and we will develop State Diagrams instead.