Changed topic structure for TNA

Author: bjahagir-OpenShift

installing/installing_two_node_cluster/about-two-node-arbiter-installation.adoc

@@ -3,6 +3,7 @@
 = Two-Node with Arbiter
 :context: about-two-node-arbiter-installation
 
+[role="_abstract"]
 An {product-title} cluster with two control plane nodes and one local arbiter node is a compact, cost-effective {product-title} topology. The arbiter node stores the full etcd data, maintaining an etcd quorum and preventing split brain. The arbiter node does not run the additional control plane components `kube-apiserver` and `kube-controller-manager`, nor does it run workloads.
 
 To install a cluster with two control plane nodes and one local arbiter node, assign an arbiter role to at least one of the nodes and set the control plane node count for the cluster to 2. Although {product-title} does not currently impose a limit on the number of arbiter nodes, the typical deployment includes only one to minimize the use of hardware resources.
@@ -11,6 +12,10 @@ After installation, you can add additional arbiter nodes to a cluster with two c
 
 You can install a cluster with two control plane nodes and one local arbiter node by using one of the following methods:
 
-* Installing on bare metal: xref:../installing_bare_metal/ipi/ipi-install-installation-workflow.adoc#ipi-install-config-local-arbiter-node_ipi-install-installation-workflow[Configuring a local arbiter node]
+* Installing on bare metal with IPI: 
+  - xref:../installing_bare_metal/ipi/ipi-install-installation-workflow.adoc#ipi-install-config-local-arbiter-node_ipi-install-installation-workflow[Configuring a local arbiter node]
 
-* Installing with the Agent-based Installer: xref:../../installing/installing_with_agent_based_installer/installing-with-agent-based-installer.adoc#installing-ocp-agent-local-arbiter-node_installing-with-agent-based-installer[Configuring a local arbiter node]
+  - xref:../installing_bare_metal/ipi/ipi-install-overview.adoc[Installation Overview]
+
+* Installing on bare metal with UPI: 
+  - xref:../../installing/installing_with_agent_based_installer/installing-with-agent-based-installer.adoc#installing-ocp-agent-local-arbiter-node_installing-with-agent-based-installer[Configuring a local arbiter node]