It looks like you know how to get your microphone setup without clipping. That you know is handled by your audio interface, not Studio One.
The signal is then recorded into Studio One. You then say the output level is really low on playback.
In Studio One 4.5, you could view the Input section and turn up the Gain control to increase the signal coming into Studio One.
You can also insert an effect on the input channel if you what to bring the level up.
You can also increase the recorded audio output level by normalizing the audio clip or dragging the clip handle up to increase the output level.