Well, nobody helped so I figured it by myself.
SWITCH
# jan/02/1970 00:34:19 by RouterOS 6.48.3
# software id = 9WAK-B8SP
#
# model = RB941-2nD
# serial number = ********
/interface bridge
add name=bridge
/interface wireless
set [ find default-name=wlan1 ] ssid=MikroTik
/interface ethernet switch port
set 0 default-vlan-id=10 vlan-header=always-strip vlan-mode=secure
set 1 default-vlan-id=20 vlan-header=always-strip vlan-mode=secure
set 2 default-vlan-id=20 vlan-header=always-strip vlan-mode=secure
set 3 default-vlan-id=10 vlan-header=add-if-missing vlan-mode=secure
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/interface bridge port
add bridge=bridge interface=ether1
add bridge=bridge interface=ether2
add bridge=bridge interface=ether3
add bridge=bridge interface=ether4
/interface ethernet switch vlan
add ports=ether1,ether4 switch=switch1 vlan-id=10
add ports=ether3,ether4 switch=switch1 vlan-id=20
/system identity
set name=SWITCH
[admin@SWITCH] >
The router is configured as below:
ROUTER
# aug/16/2021 17:05:40 by RouterOS 6.48.3
# software id = YTFL-1X3R
#
# model = RouterBOARD 941-2nD
# serial number = **********
/interface bridge
add admin-mac=CC:2D:E0:21:0F:4F auto-mac=no comment=defconf name=bridge
/interface wireless
set [ find default-name=wlan1 ] band=2ghz-b/g/n channel-width=20/40mhz-XX \
disabled=no distance=indoors frequency=auto installation=indoor mode=\
ap-bridge ssid=MikroTik-210F53 wireless-protocol=802.11
/interface vlan
add interface=ether1 loop-protect=on name=vlan1 vlan-id=10
add interface=ether1 loop-protect=on name=vlan20 vlan-id=20
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/ip pool
add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server
add address-pool=default-dhcp disabled=no interface=bridge name=defconf
/interface bridge port
add bridge=bridge comment=defconf interface=ether2
add bridge=bridge comment=defconf interface=ether3
add bridge=bridge comment=defconf interface=ether4
add bridge=bridge comment=defconf interface=pwr-line1
add bridge=bridge comment=defconf interface=wlan1
add bridge=bridge interface=vlan20
/ip neighbor discovery-settings
set discover-interface-list=LAN
/interface list member
add comment=defconf interface=bridge list=LAN
add comment=defconf interface=vlan1 list=WAN
/ip address
add address=192.168.88.1/24 comment=defconf interface=bridge network=\
192.168.88.0
/ip dhcp-client
add comment=defconf disabled=no interface=vlan1
/ip dhcp-server network
add address=192.168.88.0/24 comment=defconf gateway=192.168.88.1
/ip dns
set allow-remote-requests=yes
/ip dns static
add address=192.168.88.1 comment=defconf name=router.lan
/ip firewall filter
add action=accept chain=input comment=\
"defconf: accept established,related,untracked" connection-state=\
established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
invalid
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=accept chain=input comment=\
"defconf: accept to local loopback (for CAPsMAN)" dst-address=127.0.0.1
add action=drop chain=input comment="defconf: drop all not coming from LAN" \
in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy" \
ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy" \
ipsec-policy=out,ipsec
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" \
connection-state=established,related
add action=accept chain=forward comment=\
"defconf: accept established,related, untracked" connection-state=\
established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
connection-state=invalid
add action=drop chain=forward comment=\
"defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat \
connection-state=new in-interface-list=WAN
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" \
ipsec-policy=out,none out-interface-list=WAN
/system clock
set time-zone-name=Europe/Warsaw
/system identity
set name=ROUTER
/tool mac-server
set allowed-interface-list=LAN
[admin@ROUTER] >
And also, you will lost acces to the SWITCH after uploading this config. I have not yet discovered how to make it accessible through winbox.... Work in progress.