DOC-265 migration table and section

Author: markzegarelli

src/_data/actions/slack.yml

@@ -17,3 +17,27 @@ actions:
     - name: Icon URL
       description: The URL of the image that appears next to the User.
       default: https://logo.clearbit.com/segment.com
+config:
+  - category: Connection Settings
+    settings:
+    - name: Event Channels
+      configurable: true
+      location:
+      notes: In Slack (Actions), events and channels are set per subscription.
+    - name: Identify Template
+      configurable: true
+      location: 
+      notes: In Slack (Actions), you do not need a specific template for Identifying users. Use the Messages field to write your message, and add data from the event.
+    - name: Event Template
+      configurable: true
+      location:
+      notes: In Slack (Actions), you do not need a specific template for specific Events. Use the Filter and Messages field to specify the incoming event, and write your message with data from the event.
+    - name: Incoming Webhook URL
+      configurable: true
+      location:
+      notes: Available as a subscription-level setting on the Post Message action.
+    - name: Whitelisted Traits
+      configurable: true
+      location:
+      notes: Use the Messages field in the Post Message action to create your message with any traits from an incoming Identify call.
+

src/connections/destinations/catalog/actions-slack/index.md

@@ -41,4 +41,13 @@ Slack (Actions) provides the following benefits over the classic Slack destinati
 Combine the supported [triggers](/docs/connections/destinations/actions/#components-of-a-destination-action) with the following Slack-supported actions:
 - [Post Message](#post-message)
 
-{% include components/actions-fields.html name="slack" %}
+{% include components/actions-fields.html name="slack" %}
+
+## Migration from the classic Slack destination
+
+Follow the table below to map your existing Slack destination configuration to Slack (Actions).
+
+> warning ""
+> Slack (Actions) uses [Slack's  formatting syntax](https://api.slack.com/reference/surfaces/formatting){:target="_blank"}. This requires that you manually re-enter any messages from Slack Classic, and pick event data from the event variable picker. The handlebars syntax from Slack Classic is not compatible.
+
+{% include components/actions-map-table.html name="slack" %}