Hello [NAME] Thompson - SA , There are 2 video ports on the back of your Precision 7760 (HDMI and mini Displayport).  You also have two thunderbolt 4 ports (on the left side).  So your Precision 7760 can support to connect up to four 4K external monitors without the need of a docking station. Still want to use the WD19DCS docking station, you can review the user guide to get yourself familiarize with the functions and how to setup once it arrive. Trackball and keyboard can connect to available USB ports on your Precision 7760, no need to replace those.
How do I connect an M7760 to two 43" U4320Q monitors? I'm told I need a docking station, Dell Performance Dock- WD19DCS, but I'm trying to assure I won't be unpleasantly surprised. How do I hook things up once they arrive? Also, I'm currently using a keyboard and trackball that have individual old-style USB ports. Do I have to replace those? Thanks in advance, James
How to Connect M7760 to two 43" U4320Q