The simplest answer might be to take it back to where you bought it from and demand one in English!
Changing languages on any device can be problematic because (obviously) what's on the screen will be in a language that's unfamiliar to you. (I found it difficult enough coping when, having got the retailer to remove the existing password-locked user account on my theoretically 'new' netbook, I then found out that everything was in Portuguese. Working with Japanese might prove considerably trickier!).
However, it's possible that you might still be able to identify the relevant icons, so there's at least a chance that this might help: