NetLogo is available for Windows, Mac, and Linux machines, downloadable from the project homepage.
Windows Installer:
NetLogo runs on Windows 10, Windows 8, Windows 7 and Vista. NetLogo 5.2.1 was the last version to support Windows XP and Windows 2000.
Mac:
Mac OS X 10.8.3 or newer is required. (NetLogo 5.1 was the last version to support 10.5 and 10.4; NetLogo 5.2.1 was the last version to support 10.6 and 10.7)
Linux:
NetLogo should work on standard Debian-based and Red Hat-based Linux distributions.
In each case, NetLogo comes bundled with its own Java 8 runtime. Addtionally, it is available in both 32 and 64-bit versions for Windows and Linux. Full system requirements, for each operating system can be found here.
After downloading the correct version for your machine, either run the installer (Windows, Mac) or extract the files (Linux) to create your NetLogo directory. Inside the directory you will find executables for NetLogo and NetLogo 3D, as well as a PDF copy of the NetLogo User Manual.