ReSharper Documentation
What's the best way to quickly learn ReSharper basics?
One of the best ways is probably to watch this short video in which Hadi Hariri gives a demo of ReSharper's navigation and search, code analysis, refactorings, unit testing, code generation, and support for multiple languages and frameworks, all in about 10 minutes.
A lot more ReSharper videos are also available for you to view on the JetBrains YouTube channel. The .NET Guide provides many tips, tricks and tutorials.
In addition, you can get a solid overview of ReSharper features by watching the ReSharper Fundamentals course on Pluralsight.