How to use components and controllers in ember.js

I am new to ember.js and there is a practice challenge on an app https://github.com/tunapanda/frontend-ember-challenge

The challenges are:

1. Add an action to the Single Task Component that sends a task up to the Index Controller so it can be shown as being “pinned”
2. Add a computed property to the Index Controller so that the “completed task” count updates automatically 3.Add a button Component called ToggleComplete that toggles the text from ‘Done’ to ‘Undo’

I find the learning curve a little steep and any help will do