The operations you can perform, and the object classes you can perform them on are defined in the Administration Console, Users and Roles function. What you can do is determined by the privileges and/or role assignments that have been defined for your user.
A privilege is the ability to perform a certain operation on a particular class of object, for example to create a project, or to action a request. It can also be the ability to perform a general administrative function, such as to manage lifecycles or privileges.
A role is a set of privileges that can be assigned to one or more users, enabling them to carry out activities required for a certain position within the organization, for example Developer, or Team Leader.
For details about privileges and roles and how to use them, see Privileges and Roles.