You can set the meta data filed names in Theme Options>Portfolio. Then on each portfolio item on the right hand side there will be a meta box for Meta Data with those fields available to be filled in.
You can change the theme menu in the wordpress menus manager available in the Apearance>Menu area. Just create a menu and then save it. Then you can use the option box to the left of the menus manager to set the theme to use that menu (the dropdwon in that box).
The social links are set in the main Theme Options on the first panel.