How to use W25q32 (U4) external Flash?

[TheSnowFall]

Hi, I have a CYD (Cheap-Yellow-Display) 2432S028 display. At the U4, I am planning to use a flash chip (W25q32) which is already routed to the SDSPI bus. I am a noob in using flash chips. Moreover, it is connected to the SD bus which I have never encountered. But I want to learn. I do not know how to use it as :

1. As just an external memory device
2. Use as main flash instead of using 4Mb internal flash
3. How to use both memories(internal & external)

I generally use ESP-IDF to code ESP32. I also have good knowledge of arduino IDE. But I have never used platform.io.

Please enlighten me. I added the screenshot of the portion of the schematic of W25q32 routed to the SDSPI bus in CYD