Hi,
You didn't include all of the information we need to give you a complete answer, but are some tips. You didn't describe exactly how you physically (or wirelessly) connect your products together. Also we aren't sure which songbook software you have , but thought it might be this one (
https://itunes.apple.com/us/app/songbook-+/id447755419?mt=8).
To get started try reading one of the Intro to MIDI guides on the site like this one.
Intro to MIDI.
You need to understand MSB/LSB Bank Select and Program Change and also MIDI channels. You will want the Songbook and the Tryos to receive MIDI information on two different channels so that the information doesn't conflict with each other.
You probably have to decide which device will be the master and which two will be the slaves. If you use the Ketron as your usual way to select registrations , you can put a MSB/LSB Bank and Program Change command in the registration to select a specific song in Songbook +.
This is from Page 37 of the SongBook Manual
A typical use of this feature is that ProgramChange commands are sent from within a MIDI
style, from within a played MIDI file, or from the keyboard when a registration was selected.
SongBook+ then opens the corresponding song text. (A MIDI style can resend the same
ProgramChange over and over again while looping; this will not lead to a problem.)
SongBook+ opens a song text, if it received BankSelect commands and a ProgramChange
command as configured in the „Edit song detail“ window.
Please note that SongBook+ uses values from 0 to 127. If your keyboard uses numbers from
1 to 128 instead, you must subtract 1 to get the value to configure in SongBook+.
The commands for which Voices are called up by specific Program Changes will be in the Data Book for the Tyros. Hope that helps!