If you want to have default text inserted into each new HTML file that you create, change your project so that MacroHTML knows where that default text is:
[MACROHTML PROJECT]
DESCRIPTION=
VERSION=1.0
HTMLDEFAULT=D:\shared\sites\boilers\newfiletext.txt
[PATHS]
The HTMLDEFAULT is what you need to set. Also create a file at that location with your default text in it.
After doing this and saving the project file, ensure that you refresh the project from disk inside MacroHTML.