For the Ultimaker 2+ and Ultimaker 2 Extended+, we recommend our free slicer software Cura to prepare your 3D print files. Cura can accurately convert 3D models into 3D print files and preview the objects you want to print.
The Cura software can be found here. After downloading, open the installer and run the installation wizard to complete the installation. When opening Cura for the first time, you will be asked to select your 3D printer, the Ultimaker 2+ or Ultimaker 2 Extended+. No other configuration is required and you can directly start using Cura.