Just download the latest ATG10 installers from https://edelivery.oracle.com.
You ll need to register here first if you havnt, to start the download.
Just select the relevant 32 bit or 64 bit installers based on you windows platform.
Run the executables and it should install the ATG on your system.
Also you would require to install java1.6 and jboss5.1
Set the path to JAVA_HOME, DYNAMO_HOME, JBOSS_HOME in your environment variables.
JBoss 5.1.0 EAP
Oracle (Sun) JDK 1.6.0_31
If you have Oracle support access you can get the complete list of supported environment from following link