I was thinking I needed a intervalometer, or shutter release, for astrophotography.  I got a recommendation from Uncle Rod’s Astro Blog.  I purchased Vello Shuttterboss Version II.

But, before using for astrophotography, decided to try creating a time lapse of the sunset.  The settings for the time intervals were straightforward.  I also setup the setting for number of shots but then went back to unlimited.