Go to a page or post editor and click the button to add an item list. Search for the item and add it to the page.  Simply add the shortcode:
[ucitem_list itemids="blonderoast,darkroast,mediumroast"]

Go to a page or post editor, and click the button to add the item. Search for the item and add it to the page.  Simply add the shortcode:
[ucitem itemid="Hat"]

Go to a page or post editor, and click the button to add the price. Search for the item and add it to the page.  Simply add the shortcode:
[uc_price itemid="Hat"]

Go to a page or post editor, and click the button to add a buy button. Search for the item and add it to the page.  Simply add the shortcode:
[uc_buy_button itemid="Hat" ]

The plugin will automatically add a view cart link to the end of the primary menu.  Additionally, the plugin is programmed to recognize any link with the href value of "#viewcart", or a class of "js-view-cart-snapshot" as a view cart link.

It does it automatically.  It should find a link to the most recently added single item once the item's page is visited.

The wordpress plugin makes the assignment automatically by looking at the host address of the URL when adding an item to the cart. If the domain of the wordpress site matches a domain assigned to one of your storefront hosts, it will will use that one (i.e. - www.yourdomain.com and you have secure.yourdomain.com then it will use that sotrefront when the customer checks out).  

Alternatively, if the wordpress website domain matches the subdomain portion of your storefront using the ultracart built in host addresses, it will use that storefront: www.yourdomain.com, yourdomain.ultracartstore.com or yourdomain.ultracartdev.com if the storefront host does not exist.