docs: add more info to the backup section

Signed-off-by: Gabriele Bartolini <[email protected]>

Author: gbartolini

web/docs/backup.md

@@ -6,23 +6,40 @@ sidebar_position: 10
 
 <!-- SPDX-License-Identifier: CC-BY-4.0 -->
 
-The **Barman Cloud Plugin** adds support for **hot (online) backups** of
-PostgreSQL clusters in CloudNativePG, enabling continuous physical backup and
-WAL archiving to an **object store**—without requiring downtime. It also enables
-**Full Recovery** and **Point-in-Time Recovery (PITR)** of a Postgres cluster.
-
-Before proceeding, ensure you have reviewed the following sections of the CloudNativePG documentation:
-
-- [**Backup**](https://cloudnative-pg.io/documentation/current/backup/)
-- [**WAL Archiving**](https://cloudnative-pg.io/documentation/current/wal_archiving/)
-- [**Recovery**](https://cloudnative-pg.io/documentation/current/recovery/)
+The **Barman Cloud Plugin** enables **hot (online) backups** of PostgreSQL
+clusters in CloudNativePG, supporting continuous physical backups and WAL
+archiving to an **object store**—without interrupting write operations.
+
+It also supports both **full recovery** and **Point-in-Time Recovery (PITR)**
+of a PostgreSQL cluster.
+
+At the core is the [`ObjectStore` custom resource (CRD)](plugin-barman-cloud.v1.md#objectstorespec),
+which acts as the interface between the PostgreSQL cluster and the target
+object storage system. It allows you to configure:
+
+- **Authentication and bucket location** via the `.spec.configuration` section
+- **WAL archiving** settings—such as compression type, parallelism, and
+  server-side encryption—under `.spec.configuration.wal`
+- **Base backup options**—with similar settings for compression, concurrency,
+  and encryption—under `.spec.configuration.data`
+- **Retention policies** to manage the lifecycle of archived WALs and backups
+  via `.spec.configuration.retentionPolicy`
+
+:::tip
+For details, please refer to the
+[API reference for the `ObjectStore` resource](plugin-barman-cloud.v1.md#objectstorespec).
+:::
 
+WAL files are archived in the `wals` directory, while base backups are stored
+as **tarballs** in the `base` directory, following the
+[Barman Cloud convention](https://docs.pgbarman.org/cloud/latest/usage/#object-store-layout).
 
-TODO:
+The plugin integrates seamlessly with CloudNativePG’s `Backup` and
+`ScheduledBackup` resources, supporting backups from both primary and
+[standby instances](https://cloudnative-pg.io/documentation/current/backup/#backup-from-a-standby)
+—including designated primaries in [replica cluster topologies](https://cloudnative-pg.io/documentation/current/replica_cluster/).
 
-- explain object store
-- explain WAL archive
-- explain base backups
+## About Barman Cloud
 
 Instead of relying on a traditional, centralised Barman server, the plugin
 orchestrates backup operations directly within the Kubernetes cluster using the
@@ -34,14 +51,6 @@ following tools from the [`barman-cloud`](https://pgbarman.org) suite:
 - `barman-cloud-backup-list`
 - `barman-cloud-backup-delete`
 
-Base backups are stored as **tarballs**, and both base backups and WAL files
-can be compressed and encrypted.
-
-Backups are taken from a **primary** or **designated primary** instance in a
-`Cluster` (see
-[replica clusters](https://cloudnative-pg.io/documentation/current/replica_cluster/)
-) or, alternatively, from a [standby instance](https://cloudnative-pg.io/documentation/current/backup/#backup-from-a-standby).
-
 ## Retention Policies
 
 The Barman Cloud Plugin supports **automated cleanup of obsolete backups** via