There is currently no official Companion module for H2R Graphics V2. For now, the official way is to use a Generic HTTP request module instead.
Start off by typing Generic http into the add connection input and choose Generic HTTP Requests.
Adding a connection
Once added, you can enter a label and a base URL to connect to H2R Graphics.
Entering the base info in Companion
Be sure to check out the HTTP documentation to create that Base URL.
The HTTP API documentation explains more about the specifics of what is needed for sending requests, however here is an example of showing a lower third.
Showing a lower third