I am not from Laminar Research; just a flight simmer from downunder currently rebuilding my system using 3-43 inch televisions for the out of cockpit view on my most powerful PC and planning to use a 24 inch touch monitor (Dell P2418HT) for the running of Airmanager on my reasonably powerful PC (original X-Plane PC). Both PCs to be networked. See the reference below re Russ Barlow. My system will follow his setups.
My assumption is you intend to run Airmanager and my comments are directed towards that setup. If I am wrong then hopefully you get some benefit from the information I provide.
Firstly have a look at the following links from Michael Brown found at https://www.youtube.com/watch?v=XnXficlmKFE and also at https://www.youtube.com/watch?v=ERJ3uE7GefI You will find some useful information regarding the use and setup of the touch screen. Having viewed these links then trawl through the complete listing of videos found at https://www.youtube.com/user/col2mab/videos
In this latest link Michael has created a number of other videos that include the touch screen. To be of any benefit you will need to scroll through the listing and select what you think may be useful. He slips in the use of the touch screen when presenting discussions on setup issues. He also has a lot of other useful information as well. A set of videos "not to be sneezed at". I use Michael for a lot of useful information.
Who is Michael Brown? He operates a business called XForcePC in the USA building PCs for flight simulation with the main focus on X-Plane. Laminar Research supports and recommends this business as the most reliable PC builder in the USA using X-Plane
Now the daddy of them all, Russ Barlow. Russ is a retired pilot who became interested in flight simulation residing in the USA. I am of the opinion that Russ was responsible for the introduction of using a touch screen with Airmanager coupled or linked or more correctly networked with X-Plane.
Russ is part of the Sim Innovation team developing Airmanager. Russ was developing version 3 while the software was only being released for version 2 plus. The YouTube videos Russ has created can be found at https://www.youtube.com/user/srbarlow/videos Although the following 4 video links will give you most benefit have a look at his other videos where like Michael he has provided touch screen information within videos.
The four video links, provided by me are in order of production ie the earliest through to the last reference. The video links can be found at https://www.youtube.com/watch?v=OJ0GItVWHxQ then https://www.youtube.com/watch?v=WhosGYgREQs then https://www.youtube.com/watch?v=a7LfXqpi-I8 and finally https://www.youtube.com/watch?v=PjdgOBJ5xkQ
If you are only using one PC then connect your three screens using the HDMI connection on your graphics card and connect your touch screen to your DP connection on the same card. If you have two PCs then run Airmanager on your minor PC. but network.them.
While preparing this response a comment made by Michael, more so than Russ, came to mind whereby the USB connections on the monitor has to be connected as well to one of the PCs. In doing so it allows your mouse or touch screen effect to interact with Airmanager.
My monitor has 4 USB ports. One designated as the upstream connection direct to the PC and the 3 other ports designated as the downstream connections.
I had trouble finding this comment. I am of the opinion that it is a throw away comment imbedded in one of Michael's more recent videos.
As a final comment don't be afraid to make contact with Michael or Russ. More so with Russ. I have done so and the information was useful. As an additional source of information contact Ralph at SimInnovations based in the Netherlands. I have found Ralph to be very helpful.
I hope what I have provided is useful.
Good luck and send me a private message through X-Plane on how you solved the problem.