Amazon API Website Integration and Search query

Two questions:

• How can I integrate Amazon API into a website such as this. galleon.ph I know that this is using amazon api itemsearch as it displays 10 items at a time and anything I search (even rarely used items) can be displayed in this website.

• How are they able to return the same search results as amazon.com? ex. Keyword: [keyword]

Results: 1. Item A, 2. Item B, 3. Item C