Japanese kana keyboard documentation

Hi

I got a MacBook pro with Japanese Kana keyboard and would like to know how to type on this thing.

I mean type in Japanese.

But hardly anything works. I don't know how to type smallcase characters in Hiragana.

When I type in Katakana instead all characters come out as smallcase for some weird reason.

I also don't know how to "reach" the 4th character on a 4-character key. I tried all combinations of shift and option and command and control and ... but doesn't work.

So I'm desperately searching for the documentation for that thing. Without luck so far.

Can be in Japanese if it has to :/