What do I need to install a subwoofer into my car?

I have a 2001 Honda Civic Coupe.
I plan on installing a pair of 10" or 12" subs myself in the back seats.
As far as I know, I need:
-subs
-sub boxes
-amp
-sub installation kit

is that it? Or is there more to it? All answers appreciated, thanks.

Aftermarket radio if you don't already have one