You should be familiar with the MagicDraw program and the process to create the various diagrams, model elements, and relationships. CSV Import plugin assumes you are familiar with creating UML and SysML model elements in MagicDraw, hence, it will not validate the syntax or semantics of the imported objects. Therefore it is your responsibility to make sure your model elements and diagrams are well-formed. To achieve this, data needs to be imported in the appropriate order. In general, you import diagrams first, then model elements, then relationships.
Before you can use the CSV import plugin you will need to open an existing MagicDraw project or create a new one. The elements, diagrams, and relationships that you import will be created within this project root. If you want to place it anywhere else like a sub-package, you will need to use the plugin to create a sub-package first.
The plugin avoids duplication by allowing you to choose the Key property. Therefore, on every import, the plugin can update that element if it already exists in your model and create it if it does not. The key property identify the uniqueness of elements, so you can now have a class named Class1 with a Property element named XYZ and another class named Class2 with a Property element named XYZ. Any elements that you wish the importer to place on a diagram should have unique names at the package level since there is not a way to establish the ownership of an element and the diagram on which to place it at the same time.
Before using this plugin to create elements, you should create them by hand in a test model to ensure that you know if any other prior elements are required by the model. To be on the safe side, always make a backup of your model before running this plugin.