docs: update prerequisites files with installation and connectivity t… (envoyproxy#5094)

* docs: update prerequisites files with installation and connectivity testing steps

Signed-off-by: DeeBi9 <[email protected]>

* lint

Signed-off-by: DeeBi9 <[email protected]>

* docs: remove the Note

Signed-off-by: DeeBi9 <[email protected]>

* remove redundant code

Signed-off-by: DeeBi9 <[email protected]>

---------

Signed-off-by: DeeBi9 <[email protected]>
(cherry picked from commit 3253339)
Signed-off-by: Guy Daich <[email protected]>

Author: DeeBi9

site/content/en/latest/boilerplates/o11y_prerequisites.md

@@ -1,8 +1,9 @@
 ---
 ---
 
-Follow the steps from the [Quickstart](../tasks/quickstart) to install Envoy Gateway and the example manifest.
-Before proceeding, you should be able to query the example backend using HTTP.
+{{< readfile "./prerequisites.md" >}}
+
+---
 
 Envoy Gateway provides an add-ons Helm Chart, which includes all the needing components for observability.
 By default, the [OpenTelemetry Collector](https://opentelemetry.io/docs/collector/) is disabled.

site/content/en/latest/boilerplates/prerequisites.md

@@ -1,24 +1,69 @@
 ---
 ---
 
-Follow the steps from the [Quickstart](../tasks/quickstart) task to install Envoy Gateway and the example manifest.
-Before proceeding, you should be able to query the example backend using HTTP.
+Follow the steps below to install Envoy Gateway and the example manifest. Before
+proceeding, you should be able to query the example backend using HTTP.
 
-Verify the Gateway status:
+<details>
+<summary>Expand for instructions</summary>
 
-{{< tabpane text=true >}}
-{{% tab header="kubectl" %}}
+1. Install the Gateway API CRDs and Envoy Gateway using Helm:
 
-```shell
-kubectl get gateway/eg -o yaml
-```
+   ```shell
+   helm install eg oci://docker.io/envoyproxy/gateway-helm --version {{< helm-version >}} -n envoy-gateway-system --create-namespace
+   ```
 
-{{% /tab %}}
-{{% tab header="egctl (experimental)" %}}
+2. Install the GatewayClass, Gateway, HTTPRoute and example app:
 
-```shell
-egctl x status gateway -v
-```
+   ```shell
+   kubectl apply -f https://github.com/envoyproxy/gateway/releases/download/{{< yaml-version >}}/quickstart.yaml -n default
+   ```
 
-{{% /tab %}}
-{{< /tabpane >}}
+3. Verify Connectivity:
+
+   {{< tabpane text=true >}}
+   {{% tab header="With External LoadBalancer Support" %}}
+
+   You can also test the same functionality by sending traffic to the External IP. To get the external IP of the
+   Envoy service, run:
+
+   ```shell
+   export GATEWAY_HOST=$(kubectl get gateway/eg -o jsonpath='{.status.addresses[0].value}')
+   ```
+
+   **Note**: In certain environments, the load balancer may be exposed using a hostname, instead of an IP address. If so, replace
+   `ip` in the above command with `hostname`.
+
+   Curl the example app through Envoy proxy:
+
+   ```shell
+   curl --verbose --header "Host: www.example.com" http://$GATEWAY_HOST/get
+   ```
+
+   {{% /tab %}}
+   {{% tab header="Without LoadBalancer Support" %}}
+
+   Get the name of the Envoy service created by the example Gateway:
+
+   ```shell
+   export ENVOY_SERVICE=$(kubectl get svc -n envoy-gateway-system --selector=gateway.envoyproxy.io/owning-gateway-namespace=default,gateway envoyproxy.io/owning-gateway-name=eg -o jsonpath='{.items[0].metadata.name}')
+   ```
+
+   Port forward to the Envoy service:
+
+   ```shell
+   kubectl -n envoy-gateway-system port-forward service/${ENVOY_SERVICE} 8888:80 &
+   ```
+
+   Curl the example app through Envoy proxy:
+
+   ```shell
+   curl --verbose --header "Host: www.example.com" http://localhost:8888/get
+   ```
+
+   {{% /tab %}}
+   {{< /tabpane >}}
+
+</details>
+
+---