If the bike was originally given a "PIN" code
you can use that to start the bike in most cases.
Push the tank button until your display lights up
and use your PIN number to enable the bike.
It should work unless no pin was assigned or
you forgot the pin number.
The "Button" can be finicky, sometimes it helps
to hold down the button and the housing it is in
and release, there is a slight delay and then
you should be able to go to the PIN entry in the menu
To set the pin originally the fob is necessary
or maybe a dealer can do it.