Template for creating a bridge through virt-manager :

<network>
  <name>Bridged</name>
  <forward mode="nat">
    <nat>
      <port start="1024" end="65535"/>
    </nat>
  </forward>
  <bridge name="virbr3" stp="on" delay="0"/>
  <ip address="192.168.123.1" netmask="255.255.255.0">
    <dhcp>
      <range start="192.168.123.2" end="192.168.123.254"/>
    </dhcp>
  </ip>
</network>

Replace <name> <bridge name ip address range start end accordingly

After creating a template , use NetworkManager to add an Ethernet connection to the bridge. Then , set IPV4 configuration to automatic in guest machine.