1. Choose Start a new instance under Run.
2. A list is shown with all start events that you are allowed to trigger.
3. Clicking one of the list posts gives you access to the form associated with the chosen start event. Fill out the form and press Start to initiate a new process instance, which is an end-to-end execution of a process.
Other ways to start an instance
On the space start page the last started processes are shown to the right, click on one if the processes to start an instance or click on Show all to access the list of all the process application you have permission to trigger.
An instance for a BPMN 2.0 process can also be triggered from the Process Page, read more in the article Process Page.