Sorry, I am not quite sure what you want to do.
If you wish to put a firewall between your superstack switch and the internet, this is fine - simply connect the LAN of the firewall to the switch. (You might need a cross-over ethernet cable but if your firewall was made in the last 3 years or so you can probably use any ethernet cable.) And the WAN side of the firewall plugs into your cable modem or DSL connection etc.
If you are asking how to use a superstack switch to make it a firewall then I think the answer is that this product is a switch not a firewall.