As I already wrote, Microsoft Dynamics NAV 2015 introduce a new user interface called Microsoft Dynamics NAV Tablet Client. While the Microsoft Dynamics NAV Windows and Web Clients are designed for mouse and keyboard interaction, the Microsoft Dynamics NAV Tablet Client allows users to get access to the data they need from the touch device they prefer, but only on devices in screen sizes range, longer than 7 inches and with screen resolution 960 × 510.
One important thing, we can use new Microsoft Dynamics NAV Tablet Client on devices, regardless of their operating system. It means that we can use it on Windows tablets, but also on iPad or Android tablets.
For testing purpose, you can open Tablet Client in your browser, but for your really usage, you need to use Apps. Using of SSL is mandatory because of security issues. you can download Apps from different sites, according your platform:

You can also run Tablet Client using browser (IE11 and Chrome 36.0 for Windows are prefered), but if you run Tablet Client from browsers on iPad or Android tablets, you will not be able to download files from client and you will maybe have some other limitations. You can do it from Windows tablets, but if you want other tablets and download files, you have to run this Client from Apps. Microsoft made possibility for Tablet Client using from browser only for developing and testing purpose.
Tablet Client is multilanguage client. As on Web Client, we need to configure Tablet Client on the same way for this purpose. The language that is set for the Client comes from the Web Server Instances and you can specify it on your web.config file. That means that for one Web Server Instance, we have one language. If we want to provide multiple languages, than we have to provide multiple Web Server Instances.
In following posts, I will bring you user experience using Tablet Client.
You can find here system requirements for Tablet Client on browser and Tablet Client Apps on MSDN.