AVerMedia reorganized their support site significantly in recent years. The GL310 is an older model, so it is often hidden.
If your capture card isn't displaying video or is failing to register in your software, try these proven troubleshooting methods. Issue: "Device Not Found" or Yellow Exclamation Mark avermedia gl310 driver
Ensure there is no yellow exclamation mark next to the device name. 5. Common Troubleshooting Issues and Fixes avermedia gl310 driver