You should be able to find your answers in the help file, and/or by setting break points to watch the values of things like the .YPos property.
.YPos is measured in inches, so the end of the page might be when .YPos is greater than 10. It depends on your page size and other requirements.
.NewPage is just another method of TBaseReport and is issued the same way .PrintTab is. (You said you are using "the tab functions" which I took to mean .SetTab and .PrintTab)