The header cart and my account icons will be displayed automatically after you activate the WooCommerce plugin. Wishlist icon is enabled once you install and activate free YITH WooCommerce Wishlist plugin and compare if you install free YITH WooCommerce Compare plugin.
Cart and account links – you must setup the pages in the WooCommerce settings. Docs: https://docs.woocommerce.com/document/woocommerce-pages/
Default display (desktop)
By default the my account and cart icons are displayed in the header
On page scroll
When you scroll down, the cart and my account icons floats on the right with the scrolling page.
On the mobile devices is the cart and my account link displayed in the menu bar