Learn how to enable integrations here.
When the Template App is enabled you will be able to save collections, backlogs and boards as templates to share within your organization. This includes all board apps enabled and collection wide apps such as estimates and card colors.
To save a collection as a template click the gear button on your desired collection and press Save as template.
Then you will be able to choose a name for that template and also choose who within your organization to share it with.
To create a new collection based on a saved template press the Create collection button and you will se all collection templates saved and shared with you.
When it comes to boards and backlogs you will find the Save as template button under Options in the hamburger menu.
You also have the option to name the template after your own liking and choose whom to share it with.
And to create a a board or a backlog from a saved template just press the + icon in the top left corner and under Templates you'll find them.
Note: Files and comments doesn't follow from the original board, collection or backlog when it's saved as a template. Also, there is a 64 card limit for templates.