Creating a model

You can create a new model:

from the Models view using the contextual menu New > Model
from the main menu File > New > Model
from the main toolbar using the Open Model dropdown button, selecting the New Model item

The model creation dialog ask you to:

Select the metamodel to be used
Select a model template. A model template, optionally defined by a metamodel, allows to create pre-populated models, following a certain pattern for example.
Optionally save the newly created model

The created model is opened in an editor and you can create model elements.