You can download the update directly on your device through the Apple App Store or by using the link which follows:
The new interface allows you to tap on an unfamiliar show to see the discover panel, which gives you information on the show and individual episodes. When you tap on a particular show, you will see the first, next or latest episode depending on your history with that particular show. Clicking on an episode will show you a summary of it and you can decided if you want to watch it or not. You can swipe to the left or the right if you want to see something else.
The updated UI will also let you minimize the screen, allowing you to multi-task while the video continues to play. Navigation for television shows has also been improved to help you quickly find a specific episode of you choice. Additionally you can now playback online clips and you have improved search capabilities.
source - Hulu