Extend ToDos or Leaderboard as a template to aggregate with another Mongo Collection

As the title suggests, any ideas how to do the above?

I saw Ryan Glover MeteorChef article

https://themeteorchef.com/tutorials/dynamic-fields-using-data-in-react

on dynamically creating invoicing app as a starter but it uses old style of react, but can’t get it to work as there is no source code.

So essentially once defined, I could associate invoice1 with user1 collection and create a payload for REST post when another button is clicked.