Add docs on adding cluster

Signed-off-by: Nihal Azmain <nihal@appscode.com>

Author: Nihal-Azmain

docs/platform/guides/client-organization/create-client-organization.md

@@ -89,6 +89,48 @@ Click **Next** to continue.
 
 ## Step 4: Telemetry Configuration
 
-In the final step, review the telemetry configuration that will be applied to the organization's `orgName-monitoring` namespace, then finish to create the client organization.
+In the final step, configure the telemetry settings that will be applied to the organization's `orgName-monitoring` namespace, then finish to create the client organization.
+
+![Create Client Organization wizard — Step 4, Telemetry Configuration with monitoring type, log retention, and metrics retention periods](./images/telemetry-configuration.png)
+
+- **Select Monitoring Type** — choose the monitoring stack to provision for the organization.
+- **Logs** — set the **Retention Period** for collected logs.
+- **Metrics** — set the retention periods for collected metrics:
+  - **Yearly Retention** — how long aggregated yearly metrics are kept.
+  - **Five Minute Retention** — how long five-minute resolution metrics are kept.
+  - **One Hour Retention** — how long one-hour resolution metrics are kept.
+
+Click **Submit** to create the client organization, or **Previous** to go back.
 
 Once created, the organization appears in the **Client Organizations** list and its admin can sign in to begin using it.
+
+## Add a Cluster to an Existing Client Organization
+
+You can also assign additional clusters to a client organization after it has been created.
+
+From **Site Administration → Client Organizations**, select the organization you want to update.
+
+![Client Organizations list with the existing organizations](./images/client-org-overview.png)
+
+On the organization's details page, review its **Basic Info** and the **Clusters** it is already assigned to, then click **Add Cluster**.
+
+![Client organization details page showing Basic Info and the assigned Clusters with the Add Cluster button](./images/client-org-details.png)
+
+### Step 1: Select Cluster
+
+In the first step of the **Add Cluster** wizard, choose the cluster to assign and optionally tune where its database workloads are scheduled.
+
+![Add Cluster wizard — Select Cluster step with hub cluster, spoke cluster, and DB nodepool](./images/add-cluster-to-existing-client-org.png)
+
+- **Hub Cluster** *(required)* — the management (hub) cluster for this assignment.
+- **Spoke Cluster** *(required)* — the spoke cluster where the organization's databases run.
+- **Configure DB Nodepool** *(optional)* — key/value labels used to target specific nodes for database workloads.
+- **Tolerations** *(optional)* — add tolerations so workloads can be scheduled onto tainted nodes. Each toleration takes an **Effect**, **Key**, **Operator**, and **Value**.
+
+![Add Cluster wizard — Select Cluster step with DB nodepool and tolerations expanded](./images/add-cluster-to-existing-client-org-2.png)
+
+Click **Next** to continue.
+
+### Remaining Steps
+
+After selecting the cluster, the wizard continues with the same **Gateway Configuration** and **Telemetry Configuration** steps described above for creating a client organization. Configure them as needed, then finish to add the cluster to the organization.