Android - GreenDao create/use entity and Dao class for existing sqlite database. Use greenDao with existing db

I have an existing sqlite db schema (about 30 table) which I have to import into my Android project. I'd like to use greenDao in my code but I don't know how it's possible if I have already sqlite db created. Is it possible to work with greenDao even if I haven't my pojo/entity class generated by greenDao Generator? Could I generate them manually? I think I need also DaoMaster and DaoSession!??!

Thank you very much.