Speakers > Keyboard

I have a set of speakers that used to be hooked up to our stereo with speaker wire (They have the Black and Red wire clamps). I want to plug them into my Yamaha MM6 Keyboard, but that uses an RCA plug, and I'm confused at how to do this.

Do I simply get an adapter for the speakers/wire to plug it in (Retaining great quality of course)

Or do I need a layer in between the Speakers and Keyboard to amplify or anything (Yes, I'm very new at this)

Thanks for any and all help!