There are two ways to make customizations to your website when using the New York WordPress theme.
Live Theme Customizer
Some core theme features can be found in the theme Customizer under Appearance > Customize. These include options for:
Accent color, Header color, Logo color, Menu (and menu link) colors, Site widths, Default Page Layouts, Custom header logo, Homepage slider count, Entries style, Footer copyright, Image sizes, Shop layouts and more
Yellow Pencil Visual CSS Editor
The theme also includes the Yellow Pencil Visual CSS Style Editor premium plugin for FREE (a $25 value!). With this plugin enabled you can enter the Yellow Pencil editor where you can point, click and edit any element in the theme! To use the plugin simply install it then navigate to Appearance > Yellow Pencil Editor and start customizing!