The minimum requirements if you want to do this yourself is this:
- Basic understanding of JavaScript and JavaScript objects
- An idea of what JSON is and how it relates to JavaScript objects.
- A method of loading JSON (JSONP to use cross-domain loading) and turning it into a javascript object.
- My suggestion would be to look at using jQuery for simplicity. Check out jQuery.getJSON()
- Read the documentation for the twitch API, you can find the part you need in the documentation here.
To make sure the API returns JSONP you can simply add &callback=jsonp to the end of your API url.
If you tell me how much JavaScript you know, I might be able to give you some more specific advice.