so, let's run through this top to bottom.
1. Connected to the 12p and configure the LAN IP address on eth0 - let's assume 192.168.1.1/24 for now
2. enable DHCP and configure dhcp range to 192.168.1.100 - 192.168.1.200 (shrink/grow teh range according to your requirements) so that other devices that connect to the LAN will be given an appropriate address
3. Configure eth0 and eth1 to be part of the switch0 group
4. Connect hub to eth9 and it gets a public interface.
5. Navigate to firewall/NAT - add a masquerade rule and set eth9 as the outbound interface
if you connect a device to eth0 or eth1, it *should* now work - add more ports to switch0 according to your needs..
If you don't configure ports to be part of switch0 then all packets received on any interface will hit the main CPU to be routed/switched.
If you bundle ports into the switch0 group, then rather than hitting the main CPU, they will be offloaded to the dedicated switching CPU and dealt with there.