showing/hiding chord symbols

I have a tune (attached) with two staves, one is empty for the first half. I need chords on the top staff for a few measures and then they need to show on the lower staff. How can I make this work?
Shower (347 KB)

You should find, Peter, that you can show chord symbols on both staves by right-clicking each player in Setup mode and choosing Chord Symbols > Show for All Instruments from the context menu. You can then hide the chord symbols in the places you don’t want them to appear for each staff by selecting them and activating the ‘Hidden’ property. Hidden chord symbols allow otherwise empty staves to be hidden.