Update "building an activity" docs per new enable flow (#7215)

Author: matthova

docs/activities/Building_An_Activity.mdx

@@ -134,22 +134,6 @@ Details about installation contexts is in the [Application documentation](#DOCS_
 
 Click on **Installation** in the left sidebar, then under **Installation Contexts** make sure both "User Install" and "Guild Install" are selected. This will make sure users can launch our app's Activity across Discord servers, DMs, and Group DMs.
 
-### Enable Activities
-
-Next, we'll need to enable Activities for your app. On the left hand sidebar under **Activities**, click **Getting Started**.
-
-Review this page and press **Enable**.
-
-![Enabling Activities in Settings](activities/getting-started-activities.png)
-
-After enabling Activities, you'll see the different Activity-related pages in your app's settings under the **Activities** section. Across these pages, you'll be able to update information like supported platforms, upload assets, and configure Activity-specific settings. We'll come back to this section later in the guide to set up URL mappings.
-
-#### Default Entry Point Command
-
-When you enable Activities for your app, a [default Entry Point command](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/default-entry-point-command) called "Launch" is automatically created. This [Entry Point command](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-commands) is the primary way for users to launch your Activity in Discord.
-
-By default, interactions with this command will result in Discord opening your Activity for the user and posting a message in the channel where it was launched from. However, if you prefer to handle the interactions in your app, you can update the [`handler` field](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-handlers) or create your own. Additional details are in the Entry Point command [documentation](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-commands) and [development guide](#DOCS_ACTIVITIES_DEVELOPMENT_GUIDES/setting-up-an-entry-point-command).
-
 ### Add a Redirect URI
 
 Next, we'll add a Redirect URI, which is where a user is typically redirected to after authorizing with your app when going through the standard OAuth flow. While setting up a Redirect URI is required, the Embedded App SDK automatically handles redirecting users back to your Activity when the RPC [`authorize` command](#DOCS_DEVELOPER_TOOLS_EMBEDDED_APP_SDK/authorize) is called.
@@ -187,7 +171,6 @@ Back in your app's settings, click on **OAuth2** on the sidebar:
 <Collapsible title="Step 2 Checkpoint" icon="list" open>
 
 By the end of Step 2, make sure you have:
-- Created a Discord app with Activities enabled
 - Set up a placeholder Redirect URI
 - Added your app's Client ID and Client Secret to your project's `.env` file.
 </Collapsible>
@@ -266,7 +249,7 @@ By the end of Step 3, make sure you have:
 
 ## Step 4: Running your app in Discord
 
-Let's ensure everything is wired up correctly, then run the Activity in Discord.
+Let's ensure everything is wired up correctly, enable activities via the dev portal, and then run the Activity in Discord.
 
 ### Run your app
 
@@ -322,6 +305,21 @@ Back in your app's settings, click on the **URL Mappings** page under **Activiti
 
 Read details about URL Mapping [in the development guide](#DOCS_ACTIVITIES_DEVELOPMENT_GUIDES/url-mapping).
 
+### Enable Activities
+
+Next, we'll need to enable Activities for your app. On the left hand sidebar under **Activities**, click **Settings**.
+
+Find the first checkbox, labeled `Enable Activities`. Turn it on 🎉
+
+![Enabling Activities in Settings](activities/enable-activities.png)
+
+#### Default Entry Point Command
+
+When you enable Activities for your app, a [default Entry Point command](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/default-entry-point-command) called "Launch" is automatically created. This [Entry Point command](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-commands) is the primary way for users to launch your Activity in Discord.
+
+By default, interactions with this command will result in Discord opening your Activity for the user and posting a message in the channel where it was launched from. However, if you prefer to handle the interactions in your app, you can update the [`handler` field](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-handlers) or create your own. Additional details are in the Entry Point command [documentation](#DOCS_INTERACTIONS_APPLICATION_COMMANDS/entry-point-commands) and [development guide](#DOCS_ACTIVITIES_DEVELOPMENT_GUIDES/setting-up-an-entry-point-command).
+
+
 ### Running your Activity in Discord
 
 Now that we are pointing Discord to our locally running app, we can launch the Activity in Discord!
@@ -342,6 +340,7 @@ We're looking pretty good so far, but we haven't wired up any Discord functional
 By the end of Step 4, make sure you have:
 - Set up a public endpoint
 - Added an Activity URL Mapping in your app's settings
+- Enabled Activities for your app
 - Successfully launched your Activity in Discord
 </Collapsible>