I have a song with a 20 bar intro played solo. It's impossible to hit that 21st bar at the right time without hearing the click track for that entire time. The click track only plays for the first 2 bars then quits. How can I make it play through the first 21 bars continuously............or something else that would work? Thanks

Not sure what version of BiaB you are using, but you could place the visible metronome on the screen and use it (either with or without sound).

Options > preferences > CountIn/Met.

Set to display whole song:

I'm not a BB expert, but I think you can 'unfold' a song (make it linear) and get a little more control.
That way you could silence the measures until you want them to start.
You may also be able to use F5 to mute/unmute tracks as needed.
I'm sure someone will be along with a better solution, but that's the first things I'd try.

/edit
I may have misunderstood issue, see Trevor's post above

I have the "count in/met" window pull-down set just like VT suggests, but the side hit (click) stops at bar 1. The visual works fine, but I need to hear it.

I'm thinking if count-in is a style. I can change to that style at bar 1.......then back to the original style at bar 21. Does anyone know if count-in is a style? Or of something else that sounds like the count-in clicks.

Maybe I can make one, but I've never done anything like that.

In Trevor's post above, look the the very bottom of his image.
There is an 'Audible Metronome' setting
maybe you need to enable that (or set to record/play as desired) so you hear it for the rest of the song (?)

Like this:

Try this;
Load up the appropriate BLANK MIDI style in BIAB then, using Stylemaker make yourself a click track, rename and save.
Use F5/Bar settings to play this Style for 20 bars then set the instrument style to come in at bar 21.

Vintage

Make your first chord in bar 1 like this C..D That will hold or mute everything but drums until your next chord entry which will be at bar 21. At bar 21 enter your chord as normal. Now fish through the midi styles for a basic drum beat that works well enough for a metronome. Make that the style for this song. Save it. Make a style change at bar 21. Choose the style you want for your accompaniment. Save the song again.