Missing "NI Veristand" folder in vi.lib (C:\Program Files\National Instruments\LabVIEW 2018\vi.lib)

I am trying to use custom device from github for serial communication task with PXIe 8135RT controller RS232 comm port.

I downloaded the package from below link:

https://github.com/NIVeriStandAdd-Ons/Instrument-Custom-Device

Now when I try to open the project (Instrument Addon labview project) from above package, it searches for Custom Device API.lvlib but not able to locate it, so I cannot open and mass compile the project. What is the issue? Why is it not able to locate Custom Device API.lvlib and why is it that I can not see NI Veristand folder in vi.lib folder (C:\Program Files\National Instruments\LabVIEW 2018\vi.lib)