Update index.mdx

-link to blog post for more explanation
-separate out intro and 2 ways to enable

Author: kathayl

src/content/docs/google-tag-gateway/index.mdx

@@ -6,9 +6,16 @@ sidebar:
 
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+Google tag gateway for advertisers allows website owners using Cloudflare as a CDN to get the most out of ad measurement tools with just a few clicks.
+
+Learn more about why we built it and how it works in our [blog post](https://blog.cloudflare.com/google-tag-gateway-for-advertisers/).
+
 ## Get started
 
-Google tag gateway for advertisers allows website owners using Cloudflare as a CDN to get the most out of ad measurement tools with just a few clicks. Note: setting this up [directly in Google Tag Manager](https://support.google.com/analytics/answer/16061641) is the fastest way to use this feature.
+Site owners can enable this feature in one of two ways: through the Google tag console, or via the Cloudflare dashboard. 
+
+### Configure Google tag gateway for advertisers in the Google tag console
+Setting this up [directly in Google Tag Manager](https://support.google.com/analytics/answer/16061641) is the fastest way to use this feature.
 
 ### Configure Google tag gateway for advertisers in the dashboard