This is the UML practice screen.

1. On the left is a list of objects required for that diagram. You can place it in the center area by clicking or dragging and dropping.

2. The properties window is collapsed by default on the right. When you click the square icon in the upper right corner, the properties window opens and you can change various settings of the selected object.

3. There is a toolbar at the top. You can specify zoom in/out, Undo/Redo, send object forward/backward, change color, change connector type, group objects, and more.

4. Depending on the type of UML, the contents may be changed little by little. When you mouse over a button in the corresponding toolbar, you can see the description of the button and the shortcut key for its function.

5. Use Shift + Enter to insert a line break.