Again, this is beyond the scope of this tutorial Google is your friend, as is trial and error. You may need to look through the various things listed under 'system' on one or both sides to find the thing that's actually capturing from your mic/outputting to your speakers, in which case. Choose the input ('system' on the left) and the output ('system' on the right) and click 'Connect'.This is basically a place that you can plug different Jack applications into one another so they process audio from each other. Running Jack is often a tradeoff between getting a super low latency and avoiding 'xruns', which are where Jack has to give up on processing a section of audio. This gives you information about that (and I'm sorry, but I don't know precisely what it means). Realize that Jack itself will take some time to process the sound. Check the latency in the bottom-right corner.Choosing the correct one is beyond the scope of this tutorial. Note that if you have a relatively capable soundcard, there may be a number of possible devices for it (my Audigy 2 ZS has four). Choose your soundcard/soundcards that you want to work with from the 'Input Device' and 'Output Device' dropdowns.Choose 'alsa' from the 'Driver:' dropdown.Getting Jack on Linux to connect the mic to the speakers:

Connect microphone to speakers