Add Enterprise Portal install/upgrade steps to EC v2 docs (#4174)

Add EP guided install/upgrade subsections to the v2 online install,
air gap install, and upgrade pages, matching the pattern already
used in the v3 docs.

Closes sc-134233

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AmberAlston

embedded-cluster_versioned_docs/version-2.0.0/installing-embedded-air-gap.mdx

@@ -32,7 +32,17 @@ Before you install, complete the following prerequisites:
 
 ## Install
 
-To install with Embedded Cluster in an air gap environment:
+### Use the Enterprise Portal for a guided install
+
+To use the guided install experience in the Enterprise Portal:
+
+1. Log in to the [Replicated Enterprise Portal](/vendor/enterprise-portal-about) with a user for your test customer.
+
+1. Follow the Linux install instructions for Embedded Cluster in an air gap environment.
+
+### Install using instructions from the Vendor Portal
+
+To install from the Vendor Portal:
 
 1. In the [Vendor Portal](https://vendor.replicated.com), go the channel where the target release was promoted to build the air gap bundle. Do one of the following:
      * If the **Automatically create airgap builds for newly promoted releases in this channel** setting is enabled on the channel, watch for the build status to complete.

embedded-cluster_versioned_docs/version-2.0.0/installing-embedded.mdx

@@ -16,7 +16,17 @@ Before you install, complete the following prerequisites:
 
 ## Install
 
-To install an application with Embedded Cluster:
+### Use the Enterprise Portal for a guided install
+
+To use the guided install experience in the Enterprise Portal:
+
+1. Log in to the [Replicated Enterprise Portal](/vendor/enterprise-portal-about) with a user for your test customer.
+
+1. Follow the Linux install instructions for Embedded Cluster.
+
+### Install using instructions from the Vendor Portal
+
+To install from the Vendor Portal:
 
 1. In the [Vendor Portal](https://vendor.replicated.com), go to **Customers** and click on the target customer. Click **Install instructions > Embedded Cluster**.
 

embedded-cluster_versioned_docs/version-2.0.0/updating-embedded.mdx

@@ -22,7 +22,17 @@ As shown in the diagram above, users check for available updates from the KOTS A
 
 ## Update in online clusters
 
-To perform an update with Embedded Cluster:
+### Use the Enterprise Portal for a guided upgrade
+
+To use the guided upgrade experience in the Enterprise Portal:
+
+1. Log in to the [Replicated Enterprise Portal](/vendor/enterprise-portal-about) with a user for your test customer.
+
+1. Open the **Update** tab and follow the instructions to upgrade the instance.
+
+### Update from the Admin Console
+
+To perform an update from the Admin Console:
 
 1. In the Admin Console, go to the **Version history** tab.