How to insert a text in a few shapes dynamically?

I need to create few shapes with text starting by zero. As east process is made dynamically?

There is shot example:

Slide slide = pres.GetSlideByPosition(1);
Rectangle r = slide.Shapes.AddRectangle(1000, 1000, 1000, 1000);
r.AddTextFrame(“Hello world”);

After that new created rectangle has TextFrame with default formatted
text “Hello world” so now you can change the text and formatting.