If you created a shortcut after the install, simply click it!
Did you install the chocolatey package? In that case just type
Directory on Path
Otherwise, if you added the install directory to the path, type
If you did neither of the above, use the path to which the GUI was installed:
<path to the install directory>\testcentric.exe (*)
(*) Of course, you would use a forward slash on Linux.
The trick is knowing where the GUI is installed. If you used NuGet, the installation may be in various places, depending on the environment in which you are running. Consult the NuGet documentation for more information.