How do i use my controller on gens emulator?

I am new to the emulator thing and have no idea if i am even able to use my controller on any emulators other than project 64.. if you know any other emulators for any other systems that work with game controllers please let me know... happy 420

Any emulator sets out to use just about any controller. Certain controllers give you more troubles the others. I tend to stay away from fancy controllers like logitech. And focus on basic HID (human interface device) like n642use types.