Once you've mapped your first process, you can now use it to perform that activity by creating a task. Tasks are essentially checklists that use all the information you've added to your template process to tell people what they need to do when. As the steps are done, they are ticked off and everyone is aware of the progress through the activity.
Steps that are assigned to you to complete appear in your 'My tasks' list, and you will also be notified about them by email (unless you created the task for yourself).
Some steps will be associated with a decision, which means that they can only be completed if a decision goes a certain way. In the first image above, step 4 only becomes active if the answer to the question in step 3 'Is article ready to publish' is 'Yes'. At the moment they are greyed out, so cannot be completed. Greyed out steps also don't appear in your 'My tasks' list.
When the decision means that these steps become active, this is when they will appear in your 'My tasks' list, and when you will be notified that you have steps to complete.
Next up: Reporting - Analyse your processes to see what could be improved.