@kordumb Not a dumb question at all! If your HK speakers are regular stereo/hi-fi speakers and don't have a built-in amp, then yep, you'll definitely need some kind of amp to convert the headphone/line level output on your laptop to something the speakers can use. Your Mac is already outputting lossless if it's acting as a Roon player and you're feeding it ALAC. All you have to do is give the speakers enough juice. Any old or new amp/receiver with enough output watts (based on your speakers' minimum power rating) will do it.
Or, if the HKs are computer/multimedia/powered speakers, then they likely have a 1/8" stereo cable that can plug right into your laptop and you won't need an external amp to drive them. In either case, once everything is wired up, set your laptop output to between 75% and 100% volume to give the amp/speaker setup the right level to work with. Let me know if you get stuck or if things don't sound right. This is one of the reasons I was put on the earth!