diff --git a/README.md b/README.md
index 4875cde342669f8fdf33246831b1ad9dff115ef0..f257dbdbcc7c164815e0e25515f1ea7a846d5742 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,14 @@
 # Runner setup
 
-First, the runner has to be set up as a custom runner and registered with the corresponding GitLab instance following the standard procedure. 
-The config (example in `runner_config`) needs to be adjusted to point with their `config_exec` and `run_exec` entries to the respective scripts in the runner_scripts folder. 
+First, the runner has to be set up as a custom runner and registered with the corresponding GitLab instance following the standard procedure. When prompted for "Enter an executor:", type "custom".
+
+The config (example in `runner_config`) needs to be adjusted to point with their `config_exec` and `run_exec` entries to the respective scripts in the runner_scripts folder. For a runner registered as root, the `config.toml` file is located in `/etc/gitlab-runner`; for non-root it is in `~/.gitlab-runner` ([Ref](https://docs.gitlab.com/runner/configuration/advanced-configuration.html)).
+
 Scripts need to be selected depending on runner privileges: `root` (allows change of users) or `user` (can only execute jobs as this user).
 Note, that paths in those scripts might need to be adjusted.
 
+Authentification takes place by private-public key pairs. In case of root runners, the corresponding `authorized_keys` file with the public keys needs to be in `/etc/gitlab-runner`; for non-root ones in `~/gitlab-runner/`.
+
 # Cx with `.gitlab-ci.yml`
 
 First, the username to authenticate with has to be set using the `AUTH_USER` variable.