Hi all
i have two simple questions.
First: Can i creat directory inside mysite/code? what if i want to make directory for data object and page separately. something like this: mysite/code/dataobject and mysite/code/pages

Second: in _config directory can I put any name to YML file?

The answer to both questions is yes.

Fred is correct, you can add any subfolders in the code folder, however there are a few common names I have seen and that other developers will recognise (which makes getting other SilverStripe devs involved easier as they don;t have to learn your custom structure).

/pagetypes - for your custom pagetypes
/objects - for dataobjects
/models - an alternative for dataobjects
/admin - for modeladmins
/extensions - for dataextensions or extensions
/controllers - for customer controllers

same thing applies to the yaml for example something like routes.yml should ideally contain routing configuration.

Common sense and verbose naming is key.

You can put code (.php files) in any folder (under the installation root), excepting _config.
Or unless there's a _manifest_exclude file present. Then that folder and all subfolders are skipped out by the manifest (and thus the autoloader knows nothing about the files within).

The structure is just convention for the most part. It keeps things tidy.

thank all for the reply