waveterminal u24 setup

I forgot how to connect it. Do I go: laptop usb connection to U24, toslink cable optical out to dac. RCA from DAC to preamp?

I have a macintosh, so no drivers are needed.

Yes, that is one way to go. You can also go from U24 to DAC via SPDIF (single-ended cable), which is what I do. You also may sometimes need to select the U24 as the output device in your "Sound" Preferences (most times when you plug it in it does this automatically).