To define a new collection, you need to initialize the Collection object, the first parameter is the name of the collection and the second one, the field that is going to work as primary key.
Then, in order to add new documents to the collection, (like an insert into at sql), you just need to call the save method.
This will add two documents to your collections. It is important to say that if the document already exist (based on the id Field provided), the document will be updated.
In order to get all the documents in your collection, you can use de find method.
You can use the find method with parameters in order to add some filters to the data.
This will retrieve all the tasks in which done is equal true.
Also, with the get method, it is posible to get a document based on its primary key.
An also, you can remove a document using its primary key