Activities are nodes where interaction or actions occur. Such instances could be either be human facing or a system event. For example, an activity could be a user needing to fill out a form. In the same way, an activity could equally be a system notification needing to be sent out triggered by some event.
In the context of our scenario, there are 3 activities that are required.
a. The first activity, called "Apply leave" will be played by the Requestor
b. The second activity, called "Supervisor approval" will be played by the Supervisor
c. The last activity, called "HOD approval" will be played by the HOD
Understanding that, click on the Activity icon on the left toolbar and then click on the Requestor swimlane. Once then, an activity will appear. Following that, click on the Selection icon on your left toolbar and then double click on the new activity. Once the popup window displays, change the activity's name from "Activity 1" to "Apply Leave". Once done, create a new activity each for both the Supervisor and the HOD swimlanes. Name those activities appropriate.
If done correctly, your process should look like the figure below.
