One of the cool things with Oracle VM is that Oracle offers many templates you can download from edelivery.oracle.com and import into your repository with Oracle VM Manager (OVMM). Well, since I did the same mistake that you did, that is, not reading the entire README file, I confused templates with assemblies.
Say you want to download a template for Oracle Linux 6, you have to select product pack Oracle VM Templates. The downloaded zip contains one file with extension .ova (does not mean Oracle Virtual Assembly, but Open Virtualization Format Archive). Since it is written “VM Templates” several places on the web site, it is easy to think it should be imported under VM Templates, but you need to select Assemblies as shown here and do the import from there:
Trying to import the file with extension .ova under VM Templates will fail and throw an error message at you similar to:
No VM configure file found
This is obvious if you pay attention to section 2 in the README file, that states:
2. Creating an Oracle VM Virtual Machine from the Template
The OVF based Oracle VM Templates should be imported as Assemblies.
Please review the Assemblies section of Oracle VM User’s Guide for details
about importing an assembly, and create a virtual machine template from the assembly.
Assemblies are explained in 7.5.4 in the User Guide (for version 3.2 at least).
You can create one or many VM Templates from an assembly and from there your new and shiny VMs.
By the way, one easy way to import them is to use a local HTTP server that comes with Python.