See how you can get started with analysis in ArcGIS Online. Click the following link to try spatial analysis yourself using the workflow in this video: http://ow.ly/JXgE50AD64X.
Note: This video provides an overview of analysis tools in Map Viewer Classic. For an introduction to analysis tools in Map Viewer, the modern map-making tool in ArcGIS Online, check out this video: https://mediaspace.esri.com/media/t/1_irjsfl7p