diff --git a/docs/architecture.adoc b/docs/architecture.adoc
index 2fffc40..5df3ebc 100644
--- a/docs/architecture.adoc
+++ b/docs/architecture.adoc
@@ -229,11 +229,9 @@ free:
 . Follow the instructions in https://developers.deutschebahn.com/db-api-marketplace/apis/start[So startest Du einfach mit den APIs
 ] (in German)
 
-. From the https://developers.deutschebahn.com/db-api-marketplace/apis/product[Catalog of the DB API Marketplace] subscribe to the **Timetables** API
+. From the https://developers.deutschebahn.com/db-api-marketplace/apis/product[Catalog of the DB API Marketplace] subscribe to the **Timetables** API. Note: Specifying an OAuth2 Redirect URL is not necessary.
 
-Attention:
-
-Store the API Key for APIs you subscribe to a password safe. The DB API Marketplace will not show the key later, but you can verify whether you have stored the correct key in the https://developers.deutschebahn.com/db-api-marketplace/apis/application[DB API Marketplace Applications tab].
+WARNING: Store the Client Secret (the API Key) and the Client ID for APIs you subscribe to a password safe. The DB API Marketplace will not show the key later, but you can verify whether you have stored the correct key in https://developers.deutschebahn.com/db-api-marketplace/apis/application[DB API Marketplace / Applications].
 
 ===== Register with Google Cloud Platform and Install the gcloud CLI
 
@@ -262,8 +260,10 @@ your project.
 Run]
 
    * When creating the service, connect to the (forked) GitHub repository
-   * Pass the environment variable `API_KEY` with the value of the Deutsche
-Bahn Open API Key to the Docker container. You can review your keys on the https://developer.deutschebahn.com/store/site/pages/subscriptions.jag[My Subscriptions Tab].
+   * Create an environment variable named `API_KEY` and copy the DB API **Client Secret** into it
+   * Create an environment variable named `CLIENT_ID` and copy the DB API **Client ID** into it
+
+NOTE: You can review the applications registered with your DB API Marketplace account in https://developers.deutschebahn.com/db-api-marketplace/apis/application[DB API Marketplace / Applications].
 
 == 8 Concepts
 
diff --git a/docs/user-guide.md b/docs/user-guide.md
index 411cde9..80c4ea2 100644
--- a/docs/user-guide.md
+++ b/docs/user-guide.md
@@ -18,7 +18,7 @@ Document](architecture.adoc#721-prerequisites).
 The [build pipeline](../.github/workflows/build.yml) publishes the application to [Docker
 Hub](https://hub.docker.com/r/boos/train-delays). Thus, you can pull an image and run it.
 
-Then, in the following, replace `<YOUR CLIENT ID>` and `<YOUR API KEY>` with the values displayed in the section "Berechtigungsnachweise" for your application in [DB API Marketplace / Anwendungen](https://developers.deutschebahn.com/db-api-marketplace/apis/application).
+Then, in the following, replace `<YOUR CLIENT ID>` and `<YOUR API KEY>` with the values displayed in the section "Berechtigungsnachweise" for your application in [DB API Marketplace / Applications](https://developers.deutschebahn.com/db-api-marketplace/apis/application).
 
 Note: The API Key will not be revealed. Please save the key to a password safe when creating it (see [7.2.1 Prerequisites of the Architecture
 Document](architecture.adoc#721-prerequisites)).