Terraform vwmare vcd Modules concept

could anyone please tell me the concept of Terraform vwmare vcd Modules. I have configured but getting some kind of error as mentioned below:-

│ Error: Failed to query available provider packages

│ Could not retrieve the list of available versions for provider hashicorp/vcd: provider registry registry.terraform.io does not have a
│ provider named Terraform Registry

│ Did you intend to use vmware/vcd? If so, you must specify that source address in each module which requires that provider. To see which
│ modules are currently depending on hashicorp/vcd, run the following command:
│ terraform providers