How to use Template pages

 You just need to put your page between two curly brackets : {{myPage}} 

myPage can be the node id (either node/26 or just 26) or the url alias of the page you want to include.

For example :

 {{help_template2}} 

Will output the second part of the documentation on how to use template pages.

The templates are inserted recursively, so if the page you are trying to insert contain some template as well, they will be resolved and so on.

 {{help_template3}} will insert the content of the help_template3 page {{28}} or {{node/28}} will insert the same page. 

This is the content of the page help_template3, second level of insert from help_template1

Trying to create a recursive loop of inserted template :

{{help_template2}} inserting again help_template 2

You are creating an infinite loop of include there !!! Node 27 was already added as a template !!!