Process Creation activities do not have a user interface because the engine runs them without the involvement of a user. You can not process Process Creation activities.
You can search for instances sitting in a Process Creation activity or define a view that includes them. To view the instance details select the instance in the search result or in the view. If the instance is waiting for the engine to process it you can add notes and attachments to it. If the engine is processing the instance adding a note or an attachment causes an error.
You can view information about the processing of a Process Creation activity in the audit trail.