While in the past we would put the CSV files in C:\Program Files\Inductive Automation\Ignition\data\drivers or /var/lib/ignition/data/drivers
those paths no longer are valid in Ignition 8.
The new paths are
C:\Program Files\Inductive Automation\Ignition\data\opcua\devices\(DEVICE_NAME)
DEVICE_NAME has to match the name of the device created on the OPC-UA SERVER> Devices page