...
To find the functions you will use to send and read messages from the ADC, either find the stm32f0xx_hal_spi.h file in the Drivers->STM32F0xx_HAL_Driver->Inc directory and read the function prototypes at the bottom or visit the HAL User ManualFunction APIs and look for the SPI input and output functions (IO Operations)SPI starts from p450). Also, Google is a good learning resource, as there are so many people who give examples of how to use SPI to communicate between hardware.
It is good to note that this ADC requires full duplex mode SPI communication, meaning that information will be sent to the ADC and read from it at the same time. You will need to use the SPI function that can both send and receive data.
...
Don’t forget that the ADC requires specific behavior for the CS line that is connected to the GPIO pin you set. Information for controlling a GPIO pin can be found in the HAL User ManualFunction APIs (GPIO starts from p196).
Converting ADC value to PWM signal
...