7
Just remember the structure of the module folders: <xoops_root_path>/modules/<module_folder>/<module_files>
Some modules may be packaged to be installed on the root directory, especially those that need some changes in some other files, while some need a module folder created before it can be uploaded.
Most modules come with a readme file. But if not, if you know the directory structures of the modules, and the downloaded module, you should be fine.