Can you elaborate more why it doesn't work, or send a screenshot?
Edit: If it's just a blank screen, the game downloads around 3mb before it shows anything, after so, it downloads another 2mb which is the actual game files. Try waiting a bit if your internet is that slow. It will eventually show up.
Preparing phase ends in like a second really. Here is what you can do:
1) load the game in incognito mode. (it might be that the essential files to run the game didn't load correctly and the corrupt version is cached)
2) If that doesn't solve the problem, open the Console. Right click anywhere on the page --> Insepct --> Console tab --> reload the page and show me whatever error you get.