You can use quizzly.org/typing to practice typing Japanese. They have a keyboard guide though I still had trouble getting it to work. Once working though, it didn't take much time to memorize the keyboard after printing it out and repeatedly doing tests to get my WPM up to 25.

I've never known anybody use the Japanese kana on a keyboard. Everyone I've seen just inputs in romaji and then presses the spacebar to find the appropriate kanji or word. I have a Japanese laptop with Japanese keys, but I never use these keys when typing in Japanese. I just flick a switch and it turns into Japanese and I input the words with romaji. To answer the question, there only characters the Japanese keyboard has are hiragana.

The Japanese IME (Input Method Editor) comes with the Windows operating system. Go to Regional and Language Settings in the Control Panel.

We can input them into computer in Japanese directly,but we usually input in the Roman alphabet. If you want to change Kanji,then you transform from Roman alphabet. If you want to input flower in Japanese,then you write hana,then you push the key of transformation button.Yes,we are.