How to import a Composer Template into QGIS Print Composer?

You can add items from a template by creating a new print composer and selecting the option shown in the image:

Then select your template and it should load up all the items you created.

I think there a another way.

select composer manager

then you have

instead of "composseur vide" you should have "empty composer"

So you click and select "specific".

Click on "..."

Name you new composer.