What you'd need to di is get a bit of speaker wire and attach it to the sub's terminals, you may need to unscrew it to get at them. run this throught the enclosure and out the back, ideally through an airtight gromet or set of dual speaker terminals (i have some here)
If there is anything else connected to the sub, disconnect it, as you won't need it.
You next need a power and signal wiring kit and hook this p to the amp as normal.
The Alpine amp will run in single channekl or bridged mode and this is what you're looking for, so wire up as in the manual (usually across the dual speaker outputs. and set the filters for low pass and you should be good to go.