Can I create multiple voices / have separate treble and bass lines in one track?

Unfortunately there's not currently any way to create multiple voices on a single track in Tabular. This is something that's on the to do list, though, so it will be added in a future version of the app.

In the mean time, you can either create separate tracks for each voice or use tied notes to put both voices into a single track. Apologies for the inconvenience!