it creating the laguage specific folder (syntax: <folder name>-<language name>) but it is not creating the metadata labels with language specific like "jcr:title.de"
Q2: Do content author always need to execute the translation job upon new asset upload or it is configurable automatically?
1) The asset metadata is different from the Tag metadata. The tag metadata is the global list of tags available for assets, pages, etc and is stored under /etc/tags. The Asset specific metadata usually have a "dam:" prefix and are specific to the asset.
2) The 'WCM: Sync Translation Job" workflow is invoked when you send a job for translation. So if you want to automatically start this workflow upon asset upload, you can very well integrate the workflow with the Assets workflow or just the "com.adobe.cq.wcm.translation.impl.process.SyncTranslationProcess" process into your Assets Workflow