Adding sub/amp to stock head unit

Hello all, I’ve got a MK6 GTI and recently got a new RCD330 put in and I’m thinking of adding a sub and amp, I’m interested in this one https://www.kicker.com/hideaway as it’s small and a combination of both sub and amp in one, I was just wondering how I would hook it up to the headunit as there is no RCA connections at the back, I’ve never installed a sub or amp into a stock head unit so any info would be appreciated, thanks.

I grabbed one of these https://www.scosche.com/loc90-line-output-converter for my sub install. Works fine, is cheap, and was available. Try and find something similar, I'm sure they all work the same just different build quality. You wire that into the rear speaker wires on the back of the head unit wiring harness, then splice to a power and ground. Then you've got the wire that connects to the amp to tell it when to turn on, which is wired straight to the amp. The can bus system operates that.