diff --git a/src/connections/auto-instrumentation/web-setup.md b/src/connections/auto-instrumentation/web-setup.md
index 77285f0a59..e82e57e256 100644
--- a/src/connections/auto-instrumentation/web-setup.md
+++ b/src/connections/auto-instrumentation/web-setup.md
@@ -13,15 +13,23 @@ You'll learn how to add Auto-Instrumentation sources, integrate dependencies, an
 > success "Enable Auto-Instrumentation"
 > To enable Auto-Instrumentation in your Segment workspace, reach out to your dedicated account manager.
 
-## Step 1: Add a source and get its write key
+## Step 1: Add or enable a source and get its write key
 
-You'll first need to add a source and copy its write key:
+You can either create a new source or turn on Auto-Instrumentation for an existing source. Both methods let you retrieve the `writeKey` that you’ll need later.
 
-1. In your Segment workspace, navigate to **Connections > Auto-Instrumentation** and click **Add source**.
-2. Select a source, give the source a name, and click **Save**.
-3. Return to **Connections > Sources** to view your sources.
-4. In the **My sources** table, find and click the new source you just set up.
-5. In the **Initialize the Client** section, look for and copy the `writeKey` displayed in the code block.
+### Create a new source
+
+1. In your Segment workspace, navigate to **Connections > Auto-Instrumentation**.
+2. Select **Add source**, give the source a name, and click **Save**.
+3. Return to **Connections > Sources** and select the new source you just set up.
+4. In the **Initialize the Client** section, copy the `writeKey` shown in the code block.
+
+### Enable Auto-Instrumentation on an existing source
+
+If you want to use an existing source, copy its `writeKey` from **Initialize the client**. After you install the SDK (Step 2), return to the source settings to turn on Auto-Instrumentation:
+
+- **Web:** **Connections > Sources > [source] > Settings > Analytics.js > Auto-Instrumentation** and toggle it on.
+- **Mobile:** **Connections > Sources > [source] > Settings > Advanced > Auto-Instrumentation** and toggle it on.
 
 ## Step 2: Add dependencies and initialization code