Dev tools

Before you continue it is probably a good idea to first set up the development tools needed for developing applications for the board. You will need:   
STM32Cube_FW_L4_V1.11.0\Projects\STM32L4R9I-EVAL\Applications\STemWin\MB1315\SampleDemo\
To test your toolchains you may want to build an example. I tried STM32L4R9I-EVAL-MB1315 (in the folder shown above) and it compiled fine without errors and warnings.
 

More about the hardware

The board allows access to most if not all of the device’s peripherals, which are numerous. Besides the interfaces that we have come to expect of modern MCUs (USB, UART, SPI, I2C, etc.) the board also contains more advanced peripherals like an audio CODEC with two digital microphones and two stereo outputs (the MCU can simultaneously output two independent stereo audio streams), a TFT LCD with touch, a round (smartwatch) MIPI-DSI display with touch.

Analogue I/O with LDR and potentiometer (using the MCU’s integrated opamps) together with a touch sensor is available as are pushbuttons and a tiny joystick.

Classic comms

The boards has an RS-232 port and a CAN transceiver both with 9-pin sub-D connectors; a PMOD connector gives access to SPI and UART signals, and a 4-pin (horizontal) connector is available for I2C.

A multi-function expander, ‘MFX’ in the documentation (IC16), connected to the I2C port, provides some of the signals required to control all these peripherals. 

 
ST-Link in progress
Use ST-Link to load executables into the MCU's internal flash and resource and other files into the external flash memory.

Memory

The board is loaded with all sorts of memory. The MCU itself features 2-MB Flash memory and 640 KB SRAM; on the board there is another 16-Mbit SRAM device plus 64-Mbit Octo-SPI SRAM. Additional Flash memory is available in a 128-Mbit NOR Flash device and 512-Mbit Octo-SPI Flash. EEPROM (128 KB) has not been forgotten either.

If that doesn’t suffice for your application a microSD card slot (an 8 GB card is included) and a USB OTG connector (a stylish silver and gold 4-GB pen drive is included too) allows the use of removable mass storage devices.