As we do not yet publish releases for this provider to registry.terraform.io, you have to either download a release from Github or build and install it manually as indicated below.
Make sure you have a supported version of Go installed and working.
Checkout or download this repository, then open a terminal and change to its directory.
make install
This will build the provider and place the provider binary in your plugins directory.
You are now ready to use the provider. You can find example TF configurations in this repository under the ./examples.
Alternatively, you can run:
make build
This will place the provider binary in the top level of the provider directory. You can then use it with terraform by specifying the -plugin-dir option when running terraform init
terraform init -plugin-dir /path/to/terraform-provider-alpha