Hi Brian,
This integration is alive and well. You should be able to install from the instructions at the github page. I highly recommend you take the “Curb Connect” route to integration. The instructions on github are targeted at users who have experience installing 3rd party software into SmartThings. Sounds like this would be your first adventure in that direction, so have a look here for the required background reading.
On your Curb webapp, there is an option to connect to SmartThings, but this “official” integration is completely different from my project. The official integration allows you to control SmartThings devices from the curb website. My integration gets the power usage data from Curb and makes in available in SmartThings.
Good luck!