You don't have to be an administrator to install GeoGebra but you need Java (GeoGebra is not run from binary code but from Java Virtual Machine). You can download Java here. You must be an administrator in order to install Java. Most schools have Java installed on the computers; if not, tell your system administrator to install it!
You can download GeoGebra from http://www.geogebra.org/cms/.
Download now and follow the instructions.
GeoGebra's web site also has an excellent forum.
For troubleshooting and getting access to older versions, see Reference:GeoGebra Installation FAQ.
The main feature of GeoGebra is interactivity. Since static documents such as text-documents can not capture the spirit of GeoGebra, and since most teachers/students don't have a web site of their own; it is possible to post your working to GeoGebraTube. GeoGebraTube resembles YouTube in the sense that you can share your material on Internet, the material shared is however not videos but so called GeoGebra worksheets. Worksheets on GeoGebraTube are shown as interactive applets. It is also possible for visitors to download them.
In order to share your worksheets on GeoGebraTube, you must either register to make a GeoGebra user account, or use an existing Google, Facebook
or OpenId account. You can post your material by uploading it directly to the GeoGebraTube web page, or by choosing
from within GeoGebra. Once posted, you can share it by providing a link to your GeoGebraTube User Profile, like this:
by Malin Christersson under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Sweden License