OrientDB can work in schema-less mode, schema mode or a mix of both. Here we'll discuss the schema mode. To know more about schema in OrientDB go here
Here you can :
To create a new Class, just click the New Class button. Some information is required to create the new class.
Here you can find more information about Classes
When you want to have an overview of all indexes created in your database, just click the All indexes button in the Schema UI. This will provide quick access to some information about indexes (name, type, properties, etc) and you can drop or rebuild them from here.