Update README

README.md

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 # qubes-core-admin-addon-bridge-device
+
+## Overview
+
+The bridge device allows for the establishment of local networks between various Qubes VMs, enabling seamless communication and connectivity.
+
+This repository contains **dom0 component** for creating a bridge device in Qubes OS.
+For **VM Component:**, see [qubes-core-agent-linux-addon-bridge-device](https://github.com/QubesOS-contrib/qubes-core-agent-linux-addon-bridge-device)
+
+## Installation
+
+Install this addon in *dom0* located in the `contrib` repository (see [QubesOS-contrib](https://www.qubes-os.org/doc/installing-contributed-packages/):
+```bash
+dnf install qubes-core-admin-bridge-device
+```
+
+Do the same inside your TemplateVM that will be used for creating the bridge. For example, in Fedora 39:
+```bash
+dnf install qubes-core-agent-bridge-device-network-manager
+```
+
+## Usage
+
+Once installed, you can create a bridge interface in a given AppVM (e.g., "lan-net") using NetworkManager.
+This bridge interface, named `br0` in this example, becomes available as a bridge device to be attached.
+
+### Creating a Bridge Interface
+
+```bash
+# In the AppVM named "lan-net"
+nmcli connection add type bridge ifname br0 con-name br0
+```
+
+### Viewing Available Bridges in dom0
+
+```bash
+# In dom0
+qvm-device bridge
+```
+
+### Attaching VMs to the Bridge
+
+You can attach other AppVMs (e.g., "personal") to the created bridge, establishing a local network.
+
+```bash
+# In dom0
+qvm-device bridge attach personal lan-net:br0
+```
+
+You can repeat this process for multiple VMs, creating a classical network between them.
+Additionally, physical interfaces can be attached to `br0` linking the Qubes network with external machines.
+
+### Options
+
+Options such as IP address, netmask, and gateway can be specified during attachment:
+
+```bash
+# In dom0
+qvm-device bridge attach personal lan-net:br0 --option=ip=192.168.0.1 --option=netmask=255.255.255.0 --option=gateway=192.168.0.254
+```
+
+### Important Considerations
+
+- **Bridge vs. Qubes Model:**
+  Be cautious that using the standard bridge network model differs from the Qubes model based on NAT and component isolation.
+
+- **NetVM and iptables:**
+  If your "lan-net" has a NetVM, adjustments to iptables may be necessary.