Based on your description, it sounds like it probably is just a rebranded DirecTV Genie. Also, the last DirecTV branded box was model C61, so if this is C71, it’s probably about the same thing.
In that scenario, you would just add the device manually on port 8080 as shown on the Compatibility list. You’ll need to figure out its IP on your network and enable the usual additional options as per the list.
Channel switching style is also switchable as per the Advanced setting in Devices.