diff --git a/testing/benchmark/README.md b/testing/benchmark/README.md
index c3cf50297e..0175ce6587 100644
--- a/testing/benchmark/README.md
+++ b/testing/benchmark/README.md
@@ -76,7 +76,10 @@ The main commands are:
 Helper commands
 
 - `~/.ssh/id_rsa_terraform`: Generates a new SSH key without passphrase for the worker VMs.
-- `terraform.tfvars`: Copies the examples tfvars and sets the `user_name` var with to `$USER`.
+- `terraform.tfvars`:
+    - Set `TFVARS_SOURCE` to use an explicit profile
+    - Otherwise the `terraform.tfvars.example` file is used
+    - Sets the `USER_NAME` var to `$USER`.
 - `apmbench`: Compiles the `apmbench` binary from the provided location (`APMBENCH_PATH`).
 
 ### Override the docker image  and image tag