docs: elaborate instructions for setting up hcp vault module (#163)

Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>

hcp-vault-secrets/README.md

@@ -23,7 +23,14 @@ module "vault" {
 
 ## Configuration
 
-To configure the HCP Vault Secrets module, you must create an HCP Service Principal from the HCP Vault Secrets app in the HCP console. This will give you the `HCP_CLIENT_ID` and `HCP_CLIENT_SECRET` that you need to authenticate with HCP Vault Secrets. See the [HCP Vault Secrets documentation](https://developer.hashicorp.com/hcp/docs/vault-secrets) for more information.
+To configure the HCP Vault Secrets module, follow these steps,
+
+1. [Create secrets in HCP Vault Secrets](https://developer.hashicorp.com/vault/tutorials/hcp-vault-secrets-get-started/hcp-vault-secrets-create-secret)
+2. Create an HCP Service Principal from the HCP Vault Secrets app in the HCP console. This will give you the `HCP_CLIENT_ID` and `HCP_CLIENT_SECRET` that you need to authenticate with HCP Vault Secrets.
+   ![HCP vault secrets credentials](../.images/hcp-vault-secrets-credentials.png)
+3. Set `HCP_CLIENT_ID` and `HCP_CLIENT_SECRET` variables on the coder provisioner (recommended) or supply them as input to the module.
+
+> See the [HCP Vault Secrets documentation](https://developer.hashicorp.com/hcp/docs/vault-secrets) for more information.
 
 ## Fetch All Secrets