In order to create goals and subgoals for your team simply click on Goals in the menu on the left hand side. Then select the purple button saying + New goal.
After that a window should pop up with two fields.
Goal tag (for quick tagging in tasks)
Goal title (a descriptive title for your tag)
Complish also allows you to create goal hierarchy, so that you can create all of the subgoals that are required to achieve a larger objective. To create a subgoal, all you need to do is click on the + on the left side of the goal.