The script is for the model RB2011UiAS (-IN)
First netsinstall, or at least upgrade to 6.48.6 (long-term).
Check if you are able or not to manage device with winbox by MAC address.
If yes, go to system / reset configuration and select only "no default configuration" and "do not backup" then reset configuration
When is rebooted and is "blank", open winbox by MAC and paste this on new terminal:
/interface bridge
add name=bri-wan protocol-mode=none
add name=bri-lan protocol-mode=none
/ip pool
add name=dhcp-pool ranges=192.168.30.101-192.168.30.199
/ip dhcp-server
add address-pool=dhcp-pool disabled=no interface=bri-lan lease-time=1w name=dhcp
/snmp community
set [ find default=yes ] addresses=0.0.0.0/0
/interface bridge port
add bridge=bri-wan interface=ether1
add bridge=bri-wan interface=ether10
add bridge=bri-lan interface=ether2
add bridge=bri-lan interface=ether3
add bridge=bri-lan interface=ether4
add bridge=bri-lan interface=ether5
add bridge=bri-lan interface=ether6
add bridge=bri-lan interface=ether7
add bridge=bri-lan interface=ether8
/ip address
add address=192.168.30.1/24 comment=BRI-LAN interface=bri-lan network=192.168.30.0
add address=192.168.50.254/24 comment=LAN2 interface=ether9 network=192.168.50.0
/ip dhcp-client
add disabled=no interface=bri-wan
/ip dhcp-server network
add address=192.168.30.0/24 dns-server=192.168.30.1,192.168.50.254 gateway=192.168.30.1 netmask=24
/ip dns
set allow-remote-requests=yes
/ip firewall nat
add action=masquerade chain=srcnat comment="NAT BRI-LAN" out-interface=bri-wan src-address=192.168.30.0/24
add action=masquerade chain=srcnat comment="NAT LAN2" out-interface=bri-wan src-address=192.168.50.0/24
/ip firewall service-port
set irc disabled=yes
set h323 disabled=yes
/ip ipsec policy
set 0 dst-address=0.0.0.0/0 src-address=0.0.0.0/0
/ip proxy
set parent-proxy=0.0.0.0 src-address=0.0.0.0
/ip service
set telnet disabled=yes
set ftp disabled=yes
set ssh disabled=yes
set api disabled=yes
set api-ssl disabled=yes
/system package update
set channel=long-term
/system routerboard settings
set auto-upgrade=yes