How to work with eMMC from software developer point of view
eMMC is basically an SD card packaged as a chip, so all SD card tutorials apply, however you can't use SPI, you need an SDIO controller in your MCU (or bit-banging). I would suggest to look at FatFS or FreeRTOS+FAT.

Keep in mind that (depending on the size of the settings) it may be much easier to just devote one-two flash sectors of the MCU to keep 
 the settings.