Update send-data.md

Author: samkcrespo

src/engage/journeys/send-data.md

@@ -18,6 +18,8 @@ Ensure you have connected and enabled destinations in your Space.
 3. Click **Connect destinations** to select the destination you'll send the data to.
 4. Click **Save**.
 
+To include an advertising destination in a Journey, ensure you have connected and enabled the destination within your Space, then utilize the [Show an Ad](docs/engage/journeys/step-types/#show-an-ad) step.
+
 ## Test event payloads
 
 With the Engage event tester, you can send a test event payload to a Destination. As a result, you can confirm that you've correctly configured Journey Audiences before you publish your Journey.