Cm3 emmc + sdCard

Hello! I have EMMC on the CM3 module and there is Linux Debian10. An SD card is connected to the contacts of CM3. But it is not in the system. How to enable it? Or does the SD card not work with the EMMC?

SD card should be enabled by default. Do you want to use the SD card for storage?

Yes. But it is not in the system