If you haven't already done so, go to our Download page, select a version of NUnit and download it. The Installation page contains instructions for installing on your system.
To get started using NUnit, read the Quick Start page. This article demonstrates the development process with NUnit in the context of a C# banking application. Check the Samples page for additional examples, including some in VB.Net, J# and managed C++.
NUnit has two different ways to run your tests. The console runner, nunit-console.exe, is the fastest to launch, but is not interactive. The gui runner, nunit-gui.exe, is a Windows Forms application that allows you to work selectively with your tests and provides graphical feedback.