How to get force feed back adruino

I like simulator, i wanna try to make by my own a ffb wheel. At the moment, i have done a wheel with MMOS and adruino (with open source firmware). I want to make a same firmware with new features. After reading about hdi, pdi on usb.org. I make new wheel using PDI descriptor using HDI library.
Now i don’t know how to request effect using HDI.h. I searched in src but I didn’t see HID() send_request.
How to send resquest to get effect using HDI?