Notice that there are 6 activities defined inside this business process, 4 of them are User Tasks, which means that will be handled by people. The other two are Service Tasks, which means an interaction with another system will be required.
The process diagram is self explanatory, but just in case and to avoid confusions this is what is supposed to happen for each instance of the process that is started a particular candidate:
The Human Resources Team perform the initial interview to the candidate to see if he/she fits the profile that the company is looking for.
The IT Department perform a technical interview to evaluate the candidate skills and experience.
Based on output of the Human Resources and IT teams, the accounting team create a Job Proposal which includes the yearly salary for the candidate. The proposal is created based on the output of both of the interviews (Human Resources and Technical).
As soon as the proposal has being created it is automatically sent to the candidate via email.
If the candidate accept the proposal, a new meeting is created with someone from the Human Resource team to sign the contract.
If everything goes well, as soon as the process is notified that the candidate was hired, the system will automatically post a tweet about the new Hire using the Twitter service connector.
As you can see Jack, John and Katy will be performing the tasks for this example instance of the business process, but any person inside the company that have those Roles will be able to claim and interact with those tasks.