WordPress codex has very detailed instructions on how to manage Menus. You’ll find them here.
Note: If you use our Demo Content, please, be aware that WordPress importer plugin doesn't copy theme settings, only content. So you need to set the Primary Navigation in Appearance > Menus to make it look like on our demo.
Navigation position setup
To set the position of your navigation (top and right spacing), please, follow to Theme settings > Appearance > Header.
Here's an example from Riviera theme menu settings.
Note: When use a Demo content, your menu is set automatically like on the demo site - the color is appropriate. Only navigation positioning is not.The settings can vary for different themes, so some of them may be missing.
Navigation fonts setup
Follow to Theme Settings > Appearance > Fonts > Navigation
and choose the color, fontname and size for all the navigation elements: item title, hover, dropdown, dropdown hover.
There's a font line height option as well, so you can control the vertical distance between item lines.
Don't forget to save changes.