Here is what you need to do.
- Follow the instruction at https://dialogflow.com/docs/integrations/alexa-exporter to export your DialogFlow interaction model and sample utterances and to create the skill in http://developer.amazon.com.
- You will need to create a skill service (the 'Endpoint') that calls the DialogFlow API to send and receive requests / responses between DialogFlow and the Amazon Alexa Service. I'd do that with AWS Lambda - that way you won't have to worry about configuring an SSL certificate.
After you have a skill property configured in the Amazon Developer Console you can 'enable testing' in the skill configuration to make it possible to test the skill before it's published.
Here is a video I did that walks through creating a custom Alexa skill. All of the steps in the video would apply for what you're trying to do but in addition you'd need to call the DialogFlow API using one of the DialogFlow SDKs which you can find at https://dialogflow.com/docs/sdks. If you decide to use AWS Lambda for your skill service endpoint, I'd suggest using Node.JS and the Node.JS SDK for DialogFlow.
Suggestion. If you're goal is to create a simple skill for Alexa, it might be simpler to just create the skill without DialogFlow. If you want a skill that works both for Amazon Alexa and Google Home I'd check out the Jovo Framework.
Also, for more videos on creating Alexa skills visit http://youtube.com/dabblelab or http://learn.dabblelab.com
I hope this helps!