No, you trigger the start of the process.
If you have for example:
Start -> Human Task -> Script Task -> Human Task -> end
When you call start it will cause that the Human task node will create a task in the human task server, you will need then to complete that tasks in order to the process continue to the script task.
If the script task is an automatic activity it will execute the contained code and move forward to the next Human Task.
Cheers