Creating a twitch interface should be relatively simpler if you know how to create a simple VA Plugin using the VA Framework. More information on creating a VA Plugin is available in Syn Developer Network
Once you've successfully implemented or played around with VA Plugin system then you can push forward and use any existing Twitch APIs and reference that in your VA Plugin to create a Twitch interface. A lot of the existing plugins for SVA have been open-sourced in our GitHub repository
to let developers understand the standards, integration mechanisms and design aspects of creating a VA Plugin.
You can even create your Twitch bot without relying on SVA instance by using Syn.Bot framework.