Setting up Roon to play on a second system

I am running my Roon core right now from a MacBook Pro connected to a Marantz integrated amp in a 2 channel configuration. My music is all on a Glyph 4TB Studio hard drive. I am finishing my basement and I will have another home theater system down there and I would like to be able to listen to my Roon library down there as well. My plan was to just use another MacBook hooked up via USB/DAC to a Marantz receiver. Will this work? The Glyph hard drive does not have networking capabilities.

Should do, if you install Roon in Control (Remote) function on the MacBook, I think.

how do I do that?

No, its simpler than that.
Provided both Macs are on the network, just run the second Mac as a Roon remote, with the first Mac holding the content. The drive should not be accessed by both Roons. (This way you only need one Roon license.)

Just install Roon on the second Mac, when it starts it asks if you want to connect to the first Roon (yes) or run the second one as it’s own core (no).

Anders is right. It’s very easy. You just need one core. You can configure multiple independent end points and control from any other Roon installation on the network.