Mac doesn't see Arduino Uno

Hi,

I have purchased several Arduino Unos. I have tried to mount them but IDE can't see the USB port. I have read trough this forum and I have had a suspicion that my Unos are not genuine Arduinos. I have checked it and they are not.
So can someone help me, how to make IDE see the USB and able to upload the code?
I also have an Adafruit Gemma v2, but IDE also can't seem to see that.
I am using Mac with OSX Sierra