Objects can be added either by adding a method which has a parameter that only accepts a single object type, or by pressing the icon next to a parameter to bring up the Switch Parameter Input Type interface.
Then, depending on which objects are permitted for that parameter, you can search through existing objects to be reused or copied, or add a completely new object from the selection that is given to you.
When editing the main information of an object such as its name or description, or adding and editing a method, you must press the add or edit buttons in order for the action of editing your object to be completed. If you choose for a new object to be added to one of the methods of your object then this object will not be created until you have pressed the icon to add or edit that specific method. The background of the method row will change to a light red to indicate that there are unsaved changes for your object.
When a method which contains an object is deleted, the object is not deleted. If it is unused elsewhere on the site then it will appear in the left navigation pane as an unused object. You can then reuse this object or delete it now that it is not being used anywhere else in the site.