Go to blueprints.amazon.com.au and setup an Amazon account. You will probably need a phone number for this.
Amazon will go through a fair bit of verification when setting this up for security.
When logged in you will see a page that looks like the one below
The blueprints here are templates (well blueprints) for adding your own content to the Alexa skill.
When you create your first skill make sure that you read the guide.