Project Templates can be applied when creating new, or editing existing Quotes and Projects by clicking the Add Template to Project button.

This will pop up a list of templates previously created which you can apply one or many to the Project or Quote.   You can search for a specific template. 

NOTE:  The Templates are ordered alphabetically in the Template list.  If you name your templates hierarchally, it will optimise how quickly you can find and apply them.

Once you have selected and applied the template to the project.  You can apply additional templates to the project as required by repeating this process.