After you have loaded an existing project, you probably want to create all models in it. Here is how: first specify the include folders in the project configuration. Second, right-click on the project and select Create Model. You may run into error messages, which probably mean that the project configuration is not yet entirely right. After you have created all models you can unlock them all by right-clicking the project and choosing Unlock.
Refer to Create model for more information on Batch Creation of models.