Once data suitable for MayaVi is available one can begin the visualization. If you don't have data then please note that MayaVi ships with a simple example of a heart CT scan data in the VTK data format (this should be in the examples/ directory). The dataset used is a structured points dataset with a scalar field. More VTK and PLOT3D data samples should be available from the VTK download page.
The first thing to do is load an appropriate data file. Visit the File menu and choose the appropriate menu item for the data you have and select the file you want from the resulting GUI. Once you do this, you will notice that the control panel will show a DataVizManager at the topmost list and you will see a lot of controls below this. The control panel is described in some detail in this section. If you aren't familiar with that section yet, this might be a good time to review it.
Once the data file is opened a dialog box will pop up that allows one to configure the datafile. One can choose the appropriate data field one is interested in. This configuration window can be closed when unnecessary. To reconfigure the data use the Configure Data button provided in the control panel. Only one scalar attribute and one vector attribute is supported at a given time. Each DataVizManager that is seen represents a different file. One can open as many data files as one wants. Different data types can be loaded simultaneously too. Using a similar procedure one can import a simple VRML2 scene. To close a VTK or PLOT3D file choose the appropriate file
Once the data file is read and a DataVizManager is created an instance of a ModuleManager is also created. At this point one has to load the Filters and the Modules in order to do the visualization.