1. Jump to the screen, where it's visible for Samsung Devices in activation process. You'll see the unique name of your Gear S and a small Watch Icon on the left of the name
2. Tap around 25-30 times on the Watch Icon
3. Now a short message appears saying something about bluetooth. Just ignore it, it will vanish after a few seconds
4. Now tap again on the watch icon but this time leave your finger on the screen for around 5 seconds
5. Voilà, your Gear S is now activated, you can't use it as a remote Smartwatch but as a phone watch at least.
Hope, someone figures out how to pair it with Tab S soon since this is my phone