wip: clarify how builder is used for helm air gap installs

Author: paigecalvert

docs/reference/custom-resource-helmchart-v2.mdx

@@ -89,24 +89,22 @@ For an example of recursive and non-recursive merging, see [About Recursive Merg
 
 ## builder
 
-The `builder` key is used to provide Helm values that are used during various stages of processing the Helm chart.
+The `builder` key contains the minimum Helm values required so that the output of `helm template` includes all container images needed to install and run the chart in an air-gapped environment.
 
-The `builder` key is required for the following use cases:
-
-* To create an `.airgap` bundle for installations into air gap environments.
-
-  <BuilderAirgapIntro/>
-
-  For more information, see [Package Air Gap Bundles for Helm Charts](/vendor/helm-packaging-airgap-bundles).
+The Replicated Vendor Portal uses the values in the `builder` key to run `helm template` on the chart, then parses the output to discover the list of images that the Helm chart requires. This list of required images is used to create the `.airgap` bundle for the release, and to build the Helm air gap installation instructions available in the Replicated Enterprise Portal.
 
-* To support online installations that use a local private registry, the `builder` field renders the Helm chart with all of the necessary images so that KOTS knows where to pull the images.
+The `builder` key is required for the following use cases:
 
-  You cannot prevent customers from configuring a local private registry in the Admin Console. If you think any of your customers will use a local private registry, you should use the `builder` key. For more information, see [Configuring Local Image Registries](/enterprise/image-registry-settings).
+* Air gap installations with a Replicated installer (Embedded Cluster, KOTS, kURL)
+* Air gap installations with Helm
+* Online installations with a Replicated installer where the user configured a local image registry
 
 <HelmBuilderRequirements/>
 
-* Use the same `builder` configuration to support the use of local registries in both online and air gap installations. If you already configured the `builder` key to support air gap installations, then no additional configuration is required.
-
 **Example:**
 
 <BuilderExample/>
+
+For more information about building `.airgap` bundles for installations with a Replicated installer (Embedded Cluster, KOTS, kURL), see [Package Air Gap Bundles for Helm Charts](/vendor/helm-packaging-airgap-bundles).
+
+For more information about installing with Helm in air-gapped environments, see [Install and Update with Helm in Air Gap Environments](/vendor/helm-install-airgap).

docs/vendor/helm-install-airgap.mdx

@@ -1,40 +1,36 @@
-import Prerequisites from "../partials/helm/_helm-install-prereqs.mdx"
-
 # Install and Update with Helm in Air Gap Environments
 
-This topic describes how to use Helm to install releases that contain one or more Helm charts in air-gapped environments.
+This topic describes how to use Helm to install and update releases that contain one or more Helm charts in air-gapped environments.
 
 ## Overview
 
-Replicated supports installing and updating Helm charts in air-gapped environments with no outbound internet access. In air gap Helm installations, customers are guided through the process with instructions provided in the [Replicated Download Portal](/vendor/releases-share-download-portal).
+Replicated supports installing and updating Helm charts in _air-gapped_ environments with little or no outbound internet access. In air gap Helm installations, customers are guided through the installation process with instructions provided in either the [Replicated Enterprise Portal](/vendor/enterprise-portal-about) or the [Replicated Download Portal](/vendor/releases-share-download-portal), depending on which is enabled for the customer.
 
-When air gap Helm installations are enabled, an **Existing cluster with Helm** option is displayed in the Download Portal on the left nav. When selected, **Existing cluster with Helm** displays three tabs (**Install**, **Manual Update**, **Automate Updates**), as shown in the screenshot below:
+These instructions assume that the customer is accessing the portal from a workstation that can access the internet and their internal private registry. Direct access to the target cluster is not required. The instructions also assume that the customer is familiar with `curl`, `docker`, `helm`, and `kubernetes`, and that they have some familiarity with `bash`, particularly for automating updates.
 
-![download helm option](/images/download-helm.png)
+## Prerequisites
 
-[View a larger version of this image](/images/download-helm.png)
+Before you install, complete the following prerequisites:
 
-Each tab provides instructions for how to install, perform a manual update, or configure automatic updates, respectively.
+* Declare the SDK as a dependency in your Helm chart. For more information, see [Install the SDK as a Subchart](replicated-sdk-installing#install-the-sdk-as-a-subchart) in _Installing the Replicated SDK_.
 
-These installing and updating instructions assume that your customer is accessing the Download Portal from a workstation that can access the internet and their internal private registry. Direct access to the target cluster is not required.
+* Configure the HelmChart custom resource `builder` key. This ensures that the Vendor Portal can successfully template the chart to discover the full list of container images required to install and run the chart in an air-gapped environment. The Vendor Portal uses this list of required images to create the Helm air gap installation instructions for the customer. For more information, see [builder](/reference/custom-resource-helmchart-v2#builder) in _HelmChart v2_. 
 
-Each method assumes that your customer is familiar with `curl`, `docker`, `helm`, `kubernetes`, and a bit of `bash`, particularly for automating updates.
+* The customer used to install must have the following:
 
-## Prerequisites
+     * A valid email address. This email address is only used as a username for the Replicated registry and is never contacted. For more information, see [Creating a Customer](/vendor/releases-creating-customer).
 
-Before you install, complete the following prerequisites:
+     * The **Existing Cluster (Helm CLI)** install type enabled. For more information, see [Manage Install Types for a License](licenses-install-types).
 
-<Prerequisites/>
+     * The **Helm CLI Air Gap Instructions** install option enabled.
 
 ## Install
 
-The installation instructions provided in the Download Portal are designed to walk your customer through the first installation of your chart in an air gap environment.
-
 To install with Helm in an air gap environment:
 
 1. In the [Vendor Portal](https://vendor.replicated.com), go to **Customers > [Customer Name] > Reporting**.
 
-1. In the **Download portal** section, click **Visit download portal** to log in to the Download Portal for the customer.
+1. In the **Enterprise portal** or **Download portal** section (depending on which is enabled for the customer), click **Visit** to log in to the portal.
 
 1. In the Download Portal left nav, click **Existing cluster with Helm**.