https://support.esri.com/en/Products/Desktop/arcgis-desktop/arcmap/10-6-1#knowledge-base/technicalarticle?id=000018836
getting started in ArcGIS
Just another blogs.oregonstate.edu site
Just another blogs.oregonstate.edu site
https://support.esri.com/en/Products/Desktop/arcgis-desktop/arcmap/10-6-1#knowledge-base/technicalarticle?id=000018836