- 1). Connect a MIDI-accessible device to your computer. You can use a MIDI-to-USB adapter or an external soundcard with MIDI ports (known commercially as an audio interface, available where musical instruments and equipment are sold). Connect the adapter or interface to your PC through the USB port, indicated by an image of a trident.
- 2). Connect your MIDI controller to your interface or adapter using a 5-prong MIDI cable. Connect one end of the cable to the port marked "MIDI Out" on your controller and connect the opposing end to the port marked "MIDI In" on your adapter or interface.
- 3). Install any drivers associated with your interface or adapter. Most audio interfaces include a software installation CD, including the drivers needed to communicate with your PC. If you do not install these drivers, FL Studio will not have the ability to detect your controller as an input device. Insert the CD into your computer and double-click the installer. When installation completes, eject the CD.
- 4). Open FL Studio on your computer and access your MIDI settings. Click the "Options" menu on your screen and select "MIDI Settings" from the drop-down menu. As a shortcut, you can click the F10 key on your keyboard to access the same menu.
- 5). Select your interface or adapter from the "Input" list and check the "Enable" box directly below. If your device did not include software drivers, just click the "USB Audio Device" option. Since controller devices are only concerned with transmitting MIDI notes to a secondary device, you can ignore the "Output" list at the top of your settings window.
- 6). Click the "X" in the upper-right corner of your settings window to return to your main project window. You can now use your controller as an instrument in FL Studio.
Source...