I don't use FL, but I thought it was a MIDI sequencer, no? If he has a MIDI interface he should be able to trigger the Juno from the computer, if that is what he's asking.
Again, it's not clear what you're trying to do. Basically, there are two things at play here: Audio and MIDI. If you're trying to record audio from the Juno into your computer, then Phyl has it correct, although that method, depending on your soundcard, will probably not give you the results you're hoping for. If you're trying to get FL to playback a sequence using the sounds in the Juno, then you'll need a MIDI interface of some type. The simple description of how to accomplish this is- MIDI OUT from computer to MIDI IN on Juno and MIDI OUT on Juno to MIDI IN on computer. That explanation assumes you have already installed the MIDI interface and the drivers and have configured FL to recognize it.
You need to explain what you want in more detail and tell us what your setup is.
Ted