Installation on Mac OS10.13.4 - No port option available

Hi Beginner level.

Arduino uno (genuine). Mac OS 10.13.4

I am Installing the software and setting up for the first time..
I have followed the instructions - select Tools/Port. plug in uno. Select that option for port. No additional option is shown.

I have swapped out cables. Uno is receiving power.

Can anyone help?

kind regards,


Are they both genuine UNO ?

Both unused before this problem ?

Do you get the led to light up when you plug in ?

Using the same cable for both UNO’s ( they may come up as different ports)?