Lost DUDU Dashcam APK

I had it installed professionally and it appears they did not install the APK, or give me the empty box.

Where can I find the necessary APK file so that I can use this dashcam? I have my own SD card.

I fail to mention also, I have purchased this rear parking camera: https://www.amazon.com/dp/B09FHLTVBS

Is it possible to record front and rear camera with the DVR APK? If so, how can I do this?

two diff APKs info here

Front cam recording is stored on SD card, rear on usb stick.