Problem connecting Rega Dac to Macbook 2008


I just bought a used Rega Brio-r and Rega Dac (not the -r version)
I´m trying to connect the Dac to my Macbook from 2008 but the device is not showing up on the Sound/midi settings. I run El Capitain OS.

I connected the Dac with miniToslink from Macbook 3.5mm output and Toslink into "optical in" on the Dac.

Should it automaticaly show up when I connect through the optical output or should I use "USB digital input" on the Dac and USB from Macbook? I wanted hi-def audio therefore I used the Toslink cable.

I´m not very good at this so I´m happy with all the help that you can give..
128x128philsons
The issue could very well be El Capitan, notorious for usb audio problems and still unfixed by Apple in Sierra. Google "forum el capitan audio problems" and you'll find a ton of unhappy customers. A couple of weeks ago I bought a new laptop running El Capitan and it doesn't allow me to control the volume on my USB DAC, even though it worked perfectly in Mavericks. I downloaded the app "Sound Control" that provides a partial fix but still can't run Audirvana in Integer Mode, so it's basically useless for me. The only hifi way to fix it is to go back to an earlier version of OSX which is not for the faint-hearted. My current workaround is to use my old laptop running Mavericks which I was planning to sell. 

Incidentally most people who have tried all the interface options think USB and SPDIF provide better sound than optical, despite optical being better in theory. Also if you're new to computer audio stay away from iTunes, it sounds terrible for various reasons. You can download a demo of Audirvana for free and compare the two; it's night and day, not even close. (You have to turn on Integer Mode 1 in Preferences). 
Ok but SHOULD the MacBook detect the Rega Dac through the toslink cable or is it only through USB connection? I had an Ifi microdac a few years back, connected with USB and I could find it in the settings
Every new OSX build is different. Can you check it with a friend's laptop using a previous build, Yosemite or Mavericks etc? That will tell you if El Capitan is the problem.