Note kits (instruments) allow you to play chromatically, whereas Sample Kit keyboards include a different sound on each key. Sources may span up to eight full octaves, instead of the 15 Sample Voices in a Sample Kit.
Available notes on the keyboard are outlined to show the range of the currently loaded source. Available black keys are filled in, and available white keys are outlined darker than those out of range.
As you can see in the screenshot above, the currently loaded source does not span the entire keyboard.
Since the black keys now represent notes on the keyboard such as C# or G#, Modifiers are absent from Note kits (instruments).
The ideal way to experience Arcade is with an external MIDI controller. However, you can still play Arcade using your computer's built-in qwerty keyboard if you don't have an external MIDI device.
When using Arcade in Standalone mode, your qwerty keyboard will automatically work by default.
If you are using Arcade in your DAW, look for a feature often called “Musical Typing” or "Virtual Keyboard" - here is a screenshot of the Logic Pro Musical Typing display:
For more information on Arcade's Note Engine, see our guide here.