Hi,
C8015F120 is a nice SoC, but it dosen’t have a built in usb module. So I believe your board have usb interface. There will be a usb to ttl serial converter in your board, which will be connected to the uart pins of the controller. So ineffect your pc is connected to the uart of the controller.
You will be sending command strings from the pc, compare the received string from the uart buffer and do the corresponding operation on the flash memory.
If you are new to uart, I suggest you to try out some data sending and receiving examples.
The memory chip AT49BV040B is a 8 bit parallel flash memory. You can directly connect the data pins, address pins, and control pins of the chip to the I/O pins of the controller. Thats all about the connections.
Search for some driver code for the flash. But I think you can try out yourself after reading the datasheet.