Push User Manual
You can read about Push 2 and 1 in Live's online manual.
You can also access the manual in your Live installation as a PDF. To open it, launch Live and go to: Help → Read the Live Manual...
Alternatively, you can download a PDF version of the manual below. Note that in some internet browsers the manual will be opened directly in the browser and not downloaded. To download the file, right click on the link and select Download linked file from the context menu: