Question

I read in the comment that it's complicated, I know it's complicated for this reason I asked you.

Develop Use Case, sequence, and activity diagrams based on a requirements analysis

A Web Customer can be a new customer or a registered customer. Both registered and new customers can view items from the online catalog. A new customer can sign‐up (register) for an account. Only registered customers can make a purchase. To make a purchase the customer has to view the items from the catalog first. After making a purchase the customer must checkout the items from the shopping cart. Note, that Checkout can only be done as part of making a purchase. A customer may view an item by either searching, browsing or viewing recommended items, while viewing items the customer may add the items to a shopping cart or to a wish list. Adding items to wish list and viewing recommended items requires customer authentication. A check out requires that the customer should be authenticated. Authentication can be done by user sign‐in, remember me (cookies) or single sign on. An authentication service is used in each type of authentication. Checkout also involves viewing and updating the shopping cart, calculating total, calculate shipping and making payment. The customer can pay by credit card or PayPal.

Answer 1

above images shows Use case diagram, Sequence diagram and Activity diagram respectively.