If you just specify the parameters in your Verilog-A code, when you exit the editor (after saving), it should automatically define these parameters in the CDF. When you instantiate the block, you'll probably need to use the "Use Tool Filter" cyclic field on the edit properties form, and then you should be able to see any of the parameters you defined in the VerilogA code - and you can set them on the instance.

Best Regards,

Andrew.