Top - Text A is generally for. Dojo name, Country or City
Centre - Text B is usually for your surname in Japanese. Non-Japanese names are better readable by Japanese if written in Katakana - You may prefer it in Kanji so this is also available!
Bottom - Text C is usually for your surname in alphabet, so that non-Japanese readers can recognise your name.
Any options can be left blank by simply entering "BLANK" in the corresponding field.