There are a few ways to create an objective depending on the page you're currently viewing - but the easiest way is to head to the 'My Dashboard' page and click the 'New Objective' button in the top right.
From here you can create an objective of any kind - although this does depend on your level of access to the application, for example only Team Owners will be able to create a Team objective, and only users in the administrator's security group will be able to create Company objectives.
You will also be able to create objectives from other pages such as another Objective page, although in this scenario it will follow the hierarchy of the objective you're on - for example if you are viewing a company objective, you will only be able to create a team objective, and similarly, if you're viewing a team objective, you will only be able to create an individual objective.