APFS for Windows is notan application or program – it is a filesystem driver. This means that after you installed APFS for Windows and performed a reboot it starts automatically and loads during PC startup sequence. After that driver is loaded and if you connect APFS device and there are no issues – filesystem will be recognized and drive will be mounted. After that you use standard Windows functions to change drive letter or mount/unmount devices.
The only APFS interface window is an activation window, which appears during installation or during start up sequence if you didn’t enter product number and serial number during installation.