Go to the Academic Software page of GeoGebra and choose whether you want to download and install GeoGebra, or prefer to use the online version.
Use the online version
Click on the button 'Go to GeoGebra Online' on the right. You can get started right away.
Download and install GeoGebra
Step 1: Under 'Select version' at the top right of the page, choose 'GeoGebra 6'.
Step 2: Click on the button ‘Download GeoGebra 6'.
Step 3: The installer file will download. Run this file.
Step 4: GeoGebra will start and you can start using it right away. You can remove the installer file and run the program from the Start menu.