how to delete small section in garageband editor

I’m using Garageband 10 for the first time and struggling to delete parts of my audio in the Editor.  There are regular tick marks and I can only delete sections in the increments of those tick marks.  How can I shave off smaller bits of audio from this file, independent of the tick marks?  Ultimately I would love to remove these marks altogether so I can edit without them, but at the very least would love to be able to delete with more nuance than they afford.  Thanks for your ideas.