It is the lower button of the #5 pair under the display screen. The display that opens when you initially press the 'Internet' button has icons for
these button pairs. The lower #5 has the icon 'SETTING' associated with it.
I'm not sure what you are expecting to be able to do by connecting your 3000 to the internet!
The keyboards could only ever access one specific Yamaha website (there is no general web browser in the keyboard), and this service was closed down in the middle of 2016!
Regards
Ian