Update docs w plugin info (#1992)

* Update docs w plugin info

Signed-off-by: Carlisia <carlisia@vmware.com>

* Review

Signed-off-by: Carlisia <carlisia@vmware.com>

site/docs/master/install-overview.md

@@ -46,6 +46,7 @@ _Note: if your object storage provider is different than your volume snapshot pr
 
 ## Advanced installation topics
 
+- [Plugins](#plugins)
 - [Install in any namespace](#install-in-any-namespace)
 - [Use non-file-based identity mechanisms](#use-non-file-based-identity-mechanisms)
 - [Enable restic integration](#enable-restic-integration)
@@ -56,6 +57,9 @@ _Note: if your object storage provider is different than your volume snapshot pr
 - [Generate YAML only](#generate-yaml-only)
 - [Additional options](#additional-options)
 
+#### Plugins
+
+During install, Velero requires that at least one plugin is added (with the `--plugins` flag). Please see the documentation under [Plugins](overview-plugins.md)
 
 #### Install in any namespace
 
@@ -123,7 +127,7 @@ To use a different volume snapshot provider:
 1. Add your volume snapshot provider's plugin to Velero (look in [your provider][0]'s documentation for the image name):
 
     ```bash
-    velero plugin add <PLUGIN-IMAGE>
+    velero plugin add <registry/image:version>
     ```
 
 1. Add a volume snapshot location for your provider, following [your provider][0]'s documentation for configuration:

site/docs/master/overview-plugins.md

@@ -1,18 +1,24 @@
 
 # Velero plugin system
 
-Velero has a plugin system which allows integration with a variety of providers for backup storage and volume snapshot operations. Please see the links on the left under `Plugins`.
+Velero has a plugin system which allows integration with a variety of providers for backup storage and volume snapshot operations. 
 
-Anyone can add integrations for any platform to provide additional backup and volume storage without modifying the Velero codebase.
+During install, Velero requires that at least one plugin is added (with the `--plugins` flag). The plugin will be either of the type object store or volume snapshotter, or a plugin that contains both. An exception to this is that when the user is not configuring a backup storage location or a snapshot storage location at the time of install, this flag is optional.
+
+Any plugin can be added after Velero has been installed by using the command `velero plugin add <registry/image:version>`. 
+
+Example with a dockerhub image: `velero plugin add velero/velero-plugin-for-aws:v1.0.0`.
+
+In the same way, any plugin can be removed by using the command `velero plugin remove <registry/image:version>`.
 
 ## Creating a new plugin
 
-To write a plugin for a new backup or volume storage platform, take a look at our [example repo][1] and at our documentation for [how to develop plugins][2].
+Anyone can add integrations for any platform to provide additional backup and volume storage without modifying the Velero codebase. To write a plugin for a new backup or volume storage platform, take a look at our [example repo][1] and at our documentation for [Custom plugins][2].
 
 ## Adding a new plugin
 
 After you publish your plugin on your own repository, open a PR that adds a link to it under the appropriate list of [supported providers][3] page in our documentation.
 
 [1]: https://github.com/vmware-tanzu/velero-plugin-example/
-[2]: plugins.md
+[2]: custom-plugins.md
 [3]: supported-providers.md