Essentially, upjers Playground isn't too different from the regular Portal (en.upjers.com). The layout is fairly similar.

When you first start the upjers Playground, you'll need to log in with your Portal account data using the fields in the top left area. 

Once you're logged in, you'll be able to access all of your game accounts by clicking on the desired game in the overview. It will open automatically in a new window.

Can I open several games at the same time?

If you have a 64-bit operating system, you can open more than one game by minimizing your current game window and picking another game from the overview page in upjers Playground. You can simply switch between them by minimizing/maximizing the appropriate windows.
Unfortunately, it is not possible to open several games at the same time on 32-bit operating systems.

How can I change the language?

You can change your language settings by clicking on the country flag in the top right corner. 
Note: You will only see games that are available in that language. However, if you click on a game, you'll still be able to select the different language accounts if you have more than one. The games themselves will be shown in the language of their server.

Why am I being directed to the homepage?

Some features are not integrated into upjers Playground. For example, redeeming upjers points or visiting the forums will only work in a conventional browser. If you click the links for these features, you'll be redirected to upjers.com in your default system browser.