[gambatte]

If I'm not mistaken, I cooked a couple of months ago and must have got it right the first time, an explanation comes up when you hover over the item. Most are pretty apparent and if you don't know for sure, don't check it. More room to add something you really want.

The essential stuff you really need for your phone to work is already checked when you specify your carrier, so don't uncheck anything unless you specifically don't want Windows Live or something like that. It's all about the space.