Download OSATE from this page. Unzip the archive and launch the OSATE environment.
You can install RAMSES-2 as an additional component of OSATE: click on menu Help –> Install Additional OSATE Components). Select RAMSES-2 and follow the installation steps.
Note: RAMSES is compatible with the latest stable build of OSATE.
To continue, you will need to install some of the the targets supported by RAMSES. The procedure is described on this page.
To test your installation, see how to launch a RAMSES example on this page.
Alternative installation method: RAMSES-2 update site
Another option is to install RAMSES-2 from its update-site (menu Help –> Install new Software… and Add RAMSES update-site):
Select all the projects as illustrated on this figure: