To access the Windows Store, swipe from the right side of the window to enter the Start menu. From there, you should be able to identify and enter the Windows Store. The image below shows some icons for the Store. You should be able to find one of them in your Start menu. After you entered the Store, use the search bar to search and download your favorite applications.
Regarding your second question, the Krrish 3 game isn't compatible with Windows 8. To obtain a download link for it, you can use the game's review page from Software Informer, but to run it, you need to use Compatibility Troubleshooter. This can be found in the Start menu by typing Compatibility Troubleshooter in the search bar.