You can add new projects to Portfolio → Add New in the WordPress Administration Panel.
Projects contain most of the same options as standard posts. You can read about these in the Add New Post chapter. Additionally, they contain post options specific to projects.
Project Options are found below the editor on the Edit Project page. If the Project Options are not visible, make sure they are checked inside the Screen Options area at the top.
If you are adding a new project, make sure you have saved the post before editing project options. Otherwise, the project options will not be visible.