You may want to check your distribution source to see if Open Office is included.
Suse generally uses the YaST tool and RPM format packages. Using YaST software-mangement module, search for “openoffice” and see if your installation already knows where to find OO. It probably does, and if so, select the OO packages and install.
If not, you’ll need to add the repository information. Some old directions will probably help to point you in the right direction to add the Suse-suitable repository.
If all else fails, you can download the rpms from the openoffice.org web site, but installation without the Suse metadata will probably be difficult.