After you have seen this HowTo video or read this article you will know where models can be created and how to create them.
Go to the Datamodel by clicking on the Datamodel tab on the Builder Bar.
Notice that every application starts automatically with two models: User and Role. These two are set by default.
+ Newto create new models at the top left.
The model settings appear. Name your model and give it a helptext.
Ready? Click Save and your model is created.
Notice that you can change the way models are shown. With the icons at the top right you change between a visual editor and list view option.
Now you can start adding Properties to your model!