1. The location of the SD card slots is behind the SIM Card and SIM & SD cover on the left side of the device and can be accessed by opening the door.
2. The SD card location above the SIM 1 & 2 card slot, the Micro SD card needs to be inserted with the gold contacts facing down. Do not force the card in or out of the tray as this could result in damage.
From Marshmallow onwards the SD card becomes by design with internal or portable memory options for your device, with this comes restrictions with use of the SD card in devices other than your CAT S52. Once you have Internal formatted the SD card with your device, to use in a separate device such as a PC will require re-formatting of the SD card which will erase the content.