Enter a Skill Invocation Name, which are two words you’ll use to invoke the skill.

Then give your Skill a name and select the default language.

Once you’ve completed the registration and are logged into Alexa Developer, select Alexa Skills Kit from the Alexa pull down.

The most full-featured and actively developed Alexa skill that allows you to play music from YouTube is called Alexa-YouTube, and while installing it is a fairly involved process, it’s well-documented and works well once completed. See the developers GitHub for more information and to donate.

Update: The developer of this skill says that it’s been so popular he’s now being charged so he’s asking for a $3/month donation to use the above skill or you can host the code on your own server. The Amazon Skills Kit enables developers to create and publish skills for Alexa that users can then install to extend the functionality of the Amazon Echo. While Amazon is unlikely to add direct support for YouTube playback to the Echo or Echo Dot anytime soon, you can add skills to your Echo to give you more control when playing music from YouTube.

If you’re unsatisfied with this, there are other approaches that you can take to automate the process. Add a Skill to Alexa to Control YouTube from Your Echo

Youtube music alexa