OBS is a powerfull tool than many streamers use however it takes a little work to use it with hopin.
You will need the following items downloaded and installed:
OBS (Open Broadcast Software)
The latest version of Virtual Cam Addon found: HERE
or for our Mac users OBS Mac Virtualcam
VB Audio Virtual Cable found: HERE
After downloading and installing these add-ons.
Within OBS
You will need to go into the advanced audio for one of your auto mixer channels (the gear)
Then set audio Monitoring on them all to Monitor and Output.
That's it! 
Now to start your virtual camera you go to tools Virtual Cam and hit start.
We found these configs worked best:
How to Test? You can test at any time with https://webcamtests.com/
Within your panel https://hopin.to/
You will want to select the newly setup Virtual Camera. As shown here.
Don't forget to join any test sessions scheduled before the con!
Reach out to our volunteer team if you have any other questions or issues.