Let's start with the web-based modeling tool. You can browse to https://activiti.alfresco.com and create a trial account there. When you login to the modeling tool you'll get an overview of your model repository (which is empty at first of course).
From the repository view you can directly go into the editor and start with BPMN modeling.
The editor provides a palette of BPMN elements on the left side, the property view at the bottom, the toolbar at the top and the canvas in the middle of the screen. When you click on one of the BPMN elements you'll get a quick edit menu to be able to add new BPMN elements in a convenient way and to transform or delete the selected BPMN element.
Another nice feature of the Activiti Editor is the availability of validation of the process definition via the second button from the left in the toolbar, the "V" button.
The BPMN elements that have validation errors are highlighted in red and the validation errors can be viewed by clicking on the error icon at the top of the BPMN element. This opens a popup showing the validation messages.
The Activiti Editor provides a lightweight and easy to use BPMN modeler and you can get started with this tool by signing up on the https://activiti.alfresco.com website.
The other new component in the package is the Activiti Admin application. A trial can be requested by filling in this form https://www.alfresco.com/products/activiti/trial. The Admin application provides functionality to browse through the Activiti Engine and query for specific process definitions, instances, tasks and jobs. For each entity a clear overview is provided including process variables, historic information etc.
In addition to the query and entity management capabilities, the Admin application provides an easy to use cluster configuration. For failover and performance reasons, it's often better to have at least 2 Activiti Engine instances on the same database. The Admin application makes it really easy to setup such a cluster of 2 or more Activiti Engines. When a cluster is running the Admin application provides Engine information, like number of process instances executed and the number of jobs in the queue, in addition to JVM information.
To be clear, this Enterprise offering will not change anything for the Activiti open source project. the Activiti Engine will remain fully open source. This new Enterprise offering will provide additional tools and applications around the Activiti Engine and it will provide a supported version for companies that are looking for support.
For more information about the Enterprise offering you can look at this web page http://www.alfresco.com/products/activiti