Ein paar ganz einfach Fragen zur Delphi-Unit ...

[Luckie]

{$R *.dfm}
Bindet die dfm (Formular Dateien) als Ressource ein.

private und public ist in der Hilfe wunderschön erklärt.

Zitat von Hilfe:

A private member is invisible outside of the unit or program where its class is declared. In other words, a private method cannot be called from another module, and a private field or property cannot be read or written to from another module. [..]

A public member is visible wherever its class can be referenced.