Right-click in the Graphics window to access a context menu, where the content varies depends on the currently selected node in the Model Builder. There are separate context menus for Geometry (also a separate one in the 2D sketch mode), Definitions, Materials, the physics interfaces, Multiphysics, and Mesh. For results, the context menu contains some zoom tools.

The context menu content is different depending on if there is a preselection (see Basic Selection Concepts) in the Graphics window or not. When there is a preselection, new features can be added from the menu taking the preselection as its selection. The context menu for physics, for example, only includes the features that can use the preselection. If the menu does not contain what you want, a Go To submenu is available for moving to another node in the Model Builder while keeping the preselection, if possible. You can then right-click again and select the feature you want to add.