As Engineer Joe showed the link that is the BEST option and the easiest one to expand upon.
This is something else to think about. If you use the equipment in this link, wired as indicated, and get the DCS Wifi component with the upgrade premier app (comes with free standard app) you can run LEGACY and TMCC from your phone or tablet with 99% of functions working! I love it and it makes life easier for me as I only need the phone or tablet. BUT as John stated you need two hands with a phone or tablet (at least I do).
One thing on the link picture. Since you have a Z4000 just use that on Fixed one and two. YOU DO NOT NEED TO POWER ALL FOUR CHANNELS. I would also use a Z500 or wall wart to power the AUX input.