Part 1: Creating the template
1. Create the template content in a new board
Create a new board with the starter content you'd like for your 'empty' template. Note that it's not important where this template is saved (it can be anywhere in your workspace).
2. Right click to convert the board to a template
This is done from "outside" of the board you want to convert.
Once you've done that, you'll see a new "Template" badge below the board title.
Part 2: Using the template you've created
1. Drag out a new empty board from the toolbar on the left
Once you've created the new board, double-click to open it.
2. Choose "More templates..."
3. Choose "Your custom templates"
Any templates that you create using the method above will show up in this menu each time you create a new board.
4. Select the template you created earlier
Then choose "Use this template" and you'll get a fresh copy of it you can start editing.
5. Share templates with your team
You can share template boards with your team the same as any other board. Also, any template that's inside a shared board will also appear in the templates popup for anyone who has access to it.