Violas have four strings, C,G,D and A, are an octave above cello and a fifth below violin. I don't understand how I would play the notes below low C on the sheet music. Should I just transpose the music up an octave so that the notes are actually on my instrument? Thank you
Yes, this looks like an error in transcription. I have seen pieces that get transcribed for Viola by merely changing the clef without taking into account the instrument.
For student pieces, the Viola version is often changed to a different key, usually a 5th so that the fingering matches what the violin uses.
So, transcribing up an octave can work, but this can put you into playing higher positions than you want.
The other option is to look for a better transcription that is arranged specifically for Viola, or look for it in a different key that is more suited for your instrument.