What you have selected in the image is the process definition. The instances will be displayed in the righthand panel.
The console only displays active process instances - so in the case of the hello_world example, the instance is only active for a very short time, and therefore unlikely to show up on the console.
To see instances in the console, it is best to use the 'simple_correlation' quickstart, which allows you to start a process instance using the 'ant sendhello' command, view it in the console, and then when ready complete the process instance by using the 'ant sendgoodbye' command.
Hope this helps.
Thank you very mach, Gary!! Now I understand! Thank you!