Do you need anything else to make it work, or is it functional out of the box?
needs a raspberry pi to connect to/alternatively an usb-2-i2s module and power supply
What resolution of FLAC files can it handle?
Does it resolve DSD files in any way?
Not natively, but will if you resample DSD64 to PCM
Is there software with it? Or can you download it easily?
you will need squeezelite or MPD or when usb-2-i2s most players will work if i2s module driver is loaded
Is it Windows and Mac compatible?
Only if you connect it to an usb-2-i2s module