Drupal - How to make views slideshow, shows more items per page than one

In Views Slideshow 7.x-3.0, you can find this option by selecting slideshow as your format and then clicking on settings. From there, you need to find the Action section and check "View Action Advanced Options", there you can choose how many items to display.

From your explanation, you would require a module called jCarousal. It has built-in views support too. You can configure its settings change the number of items to show per page.