Set up Pi-Hole as per the usual instructions. The complication is that the SuperHub won't let you set custom DNS servers. You could either manually set the IP address of your Pi-Hole as the DNS server on your clients or I think you can disable the DHCP server in the SuperHub. Pi-Hole has a DHCP server included so disable the DHCP server on the SH and use the Pi-Hole DHCP server instead.