Usability Testing Report Book Swap System Initial Prototype For our initial prototype, we have created the interface for both primary task and subtask as stated below, and some extra features such as checkout with QR to pay. Primary task : To search and buy secondhand books. Subtask: Manage user profile. Add desired books to wish list. Seller can post an ad to sell books. Have chat session through WhatsApp Messenger. Also have checkout session in app-purchase. We design our prototype by following Schneiderman's 8 Golden Rules : Principle 1 : Strive for consistency Maintain style of icon and the location of it in the navigation (settings, back, home, fav item) Principle 2 : Enable frequent users to use shortcuts User can use sort books by school, adding favorite books to the wish list and the page has WhatsApp button that lead to chat with seller to make a deal. Principle 3 : Offer informative feedback Has sound effect whenever user click fav item. Also, “loading page” ...