You have downloaded and unzipped the documentation all necessary files for the dynamical geometry program C.a.R. This is the short introduction into the package. For more information about other distribution packages visit the Web page.
If Java is installed on your computer, you can start C.a.R. using the program archive zirkel.jar, which you find in the directory doc_en. On most systems, a double click on this archive should start the program. If that does not work, try one of the following command in the command line.
cd doc_en
java -jar zirkel.jar
java -cp zirkel.jar Zirkel
For more information about Java, have a look the home page of C.a.R.
You are then running the latest release and the current examples. If you wish, use the previous stable release in CaR/Download.
I am sorry to hear that there could be a problem on Applet IMac with the PNG format of the new icons. If you have that problem, start the program with the "-s" parameter in the simple graphics. If it works, go to the special settings, select "old icons", and deselect "simple graphics", if that works. You then can start the program in normal way with old icons.
To view the documentation and the examples, open this link.