Instructions
Open Project 64.
Click "Options." Scroll down and click "Configure Controller Plugin."
Click the drop-down menu and select your input device.
Click the button next to each corresponding Nintendo 64 controller button and press the button on your keyboard or analog device that you want to assign to it. You have six seconds to assign each button.
Click "OK" after you have assigned each control button.
Press each button in game based on the assignments you made in the input configuration. For example, if you assigned the "W" key on the keyboard to act as the "A" button on the Nintendo 64 controller, press the "W" key in the game to use it for this purpose.