Add info about grafana add-on (#3011)

* Add info about grafana add-on

* helm installation options

* stylistic changes from review

* more styling changes from review

* styling changes

* linting fix

.spelling

@@ -201,6 +201,7 @@ accesslogs
 accounts.my
 addon
 addons
+add-ons
 strongSwan
 admissionregistration
 admissionregistration.k8s.io
@@ -548,4 +549,3 @@ gcse
 MB
 CPU
 CPUs
-add-ons

content/docs/setup/kubernetes/helm-install/index.md

@@ -63,6 +63,8 @@ via `kubectl apply`, and wait a few seconds for the CRDs to be committed in the
 1. Choose one of the following two
 **mutually exclusive** options described below.
 
+    > To customize Istio and install add-ons, use the `--set <key>=<value>` option in the helm template or install command. [Installation Options](/docs/reference/config/installation-options/) references supported installation key and value pairs.
+
 ### Option 1: Install with Helm via `helm template`
 
 1. Render Istio's core components to a Kubernetes manifest called `istio.yaml`:

content/docs/tasks/telemetry/using-istio-dashboard/index.md

@@ -6,7 +6,7 @@ keywords: [telemetry,visualization]
 ---
 
 This task shows you how to setup and use the Istio Dashboard to monitor mesh
-traffic. As part of this task, you will install the Grafana Istio add-on and use
+traffic. As part of this task, you will use the Grafana Istio add-on and
 the web-based interface for viewing service mesh traffic data.
 
 The [Bookinfo](/docs/examples/bookinfo/) sample application is used as
@@ -14,8 +14,8 @@ the example application throughout this task.
 
 ## Before you begin
 
-* [Install Istio](/docs/setup/) in your cluster and deploy an
+* [Install Istio](/docs/setup) in your cluster. If you are installing using Helm, enable the Grafana add-on `--set grafana.enabled=true` [option](/docs/reference/config/installation-options/).
-  application.
+* Deploy [Bookinfo](/docs/examples/bookinfo/) application.
 
 ## Viewing the Istio Dashboard