Hi, How to configure HEX S to make the computer connect to LHGs? Thanks
On WAN interface, you must set an address from same subnet as LHGs and set up correct gateway (to be able to use internet).
If DHCP is used on WAN side, just enable DHCP client for ether1 interface. If not, set up address manually - for example 192.168.88.4 should work (if not used by some other device) and I would expect that 192.168.88.1 is gateway address.
I can figure everything out except how to setup your router as a static DHCP client. 
/interface ethernet
set [ find default-name=ether1 ] comment=Port1 name=LGH
set [ find default-name=ether2 ] comment=LAN1-Home speed=100Mbps
set [ find default-name=ether3 ] comment=LAN1-Home speed=100Mbps
set [ find default-name=ether4 ] comment=LAN1-Home speed=100Mbps
set [ find default-name=sfp1 comment=LAN1-Home speed=1000Mbps
/interface bridge
add admin-mac=xx:xx:xx:xx:xx auto-mac=no comment=defconf name=HomeBridge
protocol-mode=none vlan-filtering=no
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/ip pool
add name=dhcp-HomeLAN ranges=192.168.8.100-192.168.8.254
/ip dhcp-server
add address-pool=dhcp-HomeLAN disabled=no interface=HomeBridge lease-time=1d
name=HoMeLAN
/interface bridge port
add bridge=HomeBridge comment=defconf interface=ether2
add bridge=HomeBridge comment=defconf interface=ether3
add bridge=HomeBridge comment=defconf interface=ether4
add bridge=HomeBridge comment=defconf interface=sfp1
/interface list member
add comment=defconf interface=LGH list=WAN
add comment=defconf interface=HomeBridge list=LAN
/ip address
add address=192.168.8.1/24 interface=homebridge network=192.168.8.0
???
/ip dhcp-client
add add-default-route=yes comment=defconf dhcp-options=hostname,clientid
disabled=no interface=LGH use-peer-dns=no use-peer-ntp=no
???
I suspect one uses IP address in this instance.
/ip address
add address=192.168.37.225 interface=LGH network=???
on WAN interface is DHCP client enabled, ISP is assigned me IP which is in the picture, internet is working but I can not connect
to LHG who are in the bridge setup
Sorry do not know how to communicate to LGH device. What king of interface does it have, RoS??
As @matuss wrote: manually set another address on WAN interface, belonging to 192.168.88.0/24 subnet. And make sure there’s no route set associated with this address.
Also verify how exactly you have src-nat configured right now. If it’s masquerade rather than src-nat, or if it’s src-nat, but no to-addresses set, you might loose internet access (can happen that router will use wrong WAN address for NATting) … in this case you’ll have to rework the src-nat rule.