The Model/View/Controller(MVC) is an architecture design pattern. Model means data, View means representation and Controller works on data and representation. MVC focuses on decouple the triad relationships among data, representation and controller.
The Model/View/Controller(MVC) originates from Smalltalk, an OO programming language.
MVC consists of three kind of objects. The Model is an internal representation of the data, the View is the screen presentation of GUI, and the Controller coordinates changes between the Model and View.
To achieve the MVC architecture in your project, you have to decouple View and Model by Controller. Your GUI as View should be designed as a module. It can be launched separately. Your data related classes as Model should be treated as a module too. Your controller classes should response to any data change on the GUI. Such design will increase reusability and flexibility.
Try to visualize that the user reacts with the GUI, a DataManager(Controller) listens to the GUI's call. If the user needs to load data, such request is sent to the DataManager, the DataManager starts loading, searching and extracting the requested data from the server and sends it back to the GUI. GUI is responsible to display data.
Here the server acts as Model, the DataManager acts as Controller and GUI acts as View. The DataManager can be used for both remote and local modes (design two constructors for both modes), the GUI can be replaced with any design and the data related classes can be packaged together and put on local and server sides. All of the three objects can be reused for other projects with little code alteration.
If you grasp such concept and skill, you will save a lot of time in designing and developing your projects in the future. This is the so-called OOA/OOD.