If you are totally new to ArcGIS, you should read What is ArcGIS? found on the Desktop Help. The best reference to ArcGIS is the Desktop Help and we encourage you to refer it to regularly. In the subpages here, we've attempted to provide you with an alternative overview of the software. You should work through these pages if you are new to GIS or if you feel like you need a refresher.
ArcGIS Desktop Online Help. You can start the Help from within ArcCatalog or ArcMap, or it can be run on its own from the Start Menu.
We cannot stress enough the value of getting accustomed to searching for the answers to your questions in the Help. Your knowledge in GIS will grow much more quickly if you will get into the habit of consulting the Help before asking your instructor or fellow students (primary learning outcome 3). We have outlined many other ways for you to get help here.
Assignments > Labs (4930/6920/6915) > Lab 01 - ArcGIS Refresher & Intro to WebGIS > Getting Organized and Oriented >