docs(operate): info on using el keys using halo (#781)

Adds section outlining support for EL CLI generated keys

task: none

docs/site/docs/operate/testnet/client.md

@@ -26,6 +26,14 @@ After adding the `halo` binary to your system, you can initialize and run the cl
 halo init --network testnet
 ```
 
+:::tip Using EigenLayer-Generated Private Keys
+
+If you are using the private keys generated by the EigenLayer CLI, you can have `halo` use them by saving them to `<home>/config/*.ecdsa.key.json` and deleting the `init` generated key file found there (`config/priv_validator_key.json`). The `halo` client will automatically pick up these keys and use them for signing transactions.
+
+You will need to pass in your password for that key when you run the client. You can do this by setting the `--eigenlayer-key-password` flag when executing the client's `run` command below.
+
+:::
+
 This command initializes the setup, creating several configuration files required for running the node. You can then run the client with the following command:
 
 ```bash