The first thing you need to start doing something useful with Umbrello UML Modeller is to create a model to work on. When you start Umbrello UML Modeller it always loads the last used model or creates a new, empty model (depending on your preferences set in the configuration dialog). This will allow you to start working right away.
If at any time you need to create a new model you can do this by selecting the entry from the menu, or by clicking on the New icon from the application toolbar. If you are currently working on a model which has been modified Umbrello UML Modeller will ask you if it should save your changes before loading the new model.
You can save your model at any time by selecting the option from the Menu or by clicking on the Save button from the application toolbar. If you need to save your model under a different name you can use the option from the Menu.
For your convenience Umbrello UML Modeller also offers you the option to automatically save your work each certain time period. You can configure if you want this option as well as the time intervals in the from Umbrello UML Modeller
For loading an already existing model you may select the option from the Menu or click on the Open icon from the application toolbar. The most recently used models are also available under the submenu in the Menu to speed up access to your most frequently used models.
Umbrello UML Modeller can only work on one model at a time, so if you ask the program to load a model for you and your current model has been modified since the last time you save it, Umbrello UML Modeller will ask you whether your changes should be saved to prevent any loss of work. You can start two or more instances of Umbrello UML Modeller at any one time, you can also copy and paste between instances.