Add Reverse ETL steps

Author: pwseg

src/segment-app/extensions/dbt.md

@@ -10,7 +10,7 @@ With Segment's dbt integration, you can:
 - Use centralized dbt models to set up Reverse ETL.
 - Trigger Reverse ETL syncs from dbt jobs.
 
-<!-- This page explains... -->
+This page explains how to set up a dbt Model and then use the model with Reverse ETL.
 
 > info ""
 > Extensions, including Segment's dbt integration, is currently in public beta and is governed by Segment's [First Access and Beta Preview Terms](https://www.twilio.com/en-us/legal/tos){:target="_blank"}.
@@ -34,7 +34,7 @@ To set up the dbt integration, you'll need:
 
 Follow these steps to connect the Git repository that stores your dbt Models:
 
-1. In your Segment Workspace, go to **Settings > Extensions**.
+1. In your Segment Workspace, navigate to **Settings > Extensions**.
 2. Click **Set up Git sync**.
 3. On the **Configure service credentials** page, select a service and protocol, add your SSH private key, then click **Next**.
 4. In the **Connect source** window, select a Reverse ETL warehouse source from the dropdown, then click **Save**.
@@ -47,6 +47,23 @@ You can also use dbt Cloud to schedule Reverse ETL syncs after a dbt Cloud job s
 
 To set up dbt Cloud:
 
-1. In your Segment Workspace, go to **Settings > Extensions**.
+1. In your Segment Workspace, navigate to **Settings > Extensions**.
 2. Click **Manage dbt CLoud**.
 3. Add your dbt Cloud API key, and, optionally, a custom subdomain. Click **Save**.
+
+### Model syncs
+
+After you set up dbt, Segment runs an initial sync to load models from your connected Git repository. This initial sync lets you use the most recent models when you set up Reverse ETL. In addition to Segment's initial dbt sync, you can also trigger manual dbt model syncs.
+
+### Use a model with Reverse ETL
+
+After you've successfully set up dbt with a warehouse and connected to your Git repository, you can select dbt models for use with Reverse ETL by following these steps:
+
+1. In your Segment Workspace, navigate to **Connections > Sources** and select the Reverse ETL tab. 
+2. Click **+Add Reverse ETL source** , select your source, then click **Add Model**.
+3. Click **dbt Models** as your modeling method, then select and preview a model from the dbt model dropdown.
+4. Add a primary key, then click **Preview your model**. 
+5. Click **Next**.
+6. Enter your **Model Name**, then click **Create Model**.
+
+To change a connected model, ensure that you've removed it from all active Reverse ETL syncs.