You need to use a sampler. In Studio One, it's called "Sample One XT" which is not in Prime, it is in Artist and Professional.
You need to record yourself playing each note, edit it down so you have the attack and decay just right in the waveform.
Then you can load Sample One, select your custom made preset so you can trigger it as a single instrument via MIDI or using Mouse to pain in notes on the note grid in the sequencer.
Here's a video on YouTube that shows you his in real time