Documentation: manage charts and theme selection
Documentation: install and update the extension
Documentation: create, edit a person and chart organization
Documentation: insert a chart in editor, themes overview
If your flow chart is too large (width) and some person are going on the line bellow they should be, you can click the checkbox: "disable the responsive mode"
Then a zoom feature will be enabled on you flow chart.
Yes it is, most of the time it depends of the theme you're using, not the extension.