I want to learn how to create an attribute table on ArcGIS pro in order to create a time series map. I hope to eventually display and present this time series through a story map.
Hi -- I think this might be a better question for the ArcGIS Pro community, so I'd recommend posting your question there for suggestions of how to create your time-enabled map.
Once you create your layers/map, you can read about suggestions for representing time in a story map in this blog: Showing Time in Story Maps
Use Get started with time—ArcGIS Pro | Documentation to begin exploring how to work with time in ArcGIS Pro maps. To get some practice, try the Visualize temporal data—ArcGIS Pro | Documentation quick-start tutorial!
Hope this helps.
Are you working with raster or vector data? If it is a raster, as I suspect, it can't be a floating point raster and the raster must have integer values. Then you need to run a geoprocessing tool called Build Raster Attribute Table to create the attribute table.