hola amigos!let me explain how Japanese characters are composed:)
basically, we have 3 kinds of characters. im gonna explain them by using my name here.
first, we have a character called "kanji" which is a character from china. (its also called chinese character). for example, i can write my name as 高橋 萌.
there are many lines and looks very complicated (because its from china:P). each character has its own meaning. so, we mostly use "kanji" for independent words.
there are thousands of thousands of "kanji" and its impossible to remember all...i can say we learn at least 2000 of them when we graduate from high school.
second, we have a character called "hiragana" which is a simple form of "kanji". this is the ones from your pictures:) for example, i can write my name as たかはし もえ.
its really simple compared to "kanji", right?:) thats why all foreigners start learning Japanese from this. each character has no meaning, its mostly just for the sound.
so, we use "hiragana" basically for attached words.(like particles, auxiliary verbs, to help verbs something like that) there are 46 characters in "hiragana".
thirdly, we have a character called "katakana" which is also a simple form of "kanji". for example, i can write my name as タカハシ モエ. it looks sharp compared to "hiragana" which looks more rounded.
we have also 46 characters for this and each character has no meaning like "hiragana". so basically, you can think "hiragana" and "katakana" are the same but the form is just a little different.
we use this "katakana" mostly for the words from foreign country. so your names are written in "katakana" because they are foreign names.
Seigi is セルジ and Jordi is ジョルディ.
we use these 3 kinds of characters randomly in a sentence. why we have this complicated system? its from all the history. and it looks beautiful, right?;)
頑張って下さいね:) (Good luck!)
well...i hope it makes sense to you guys, amigos:) if you have any questions, just let me know and i'd be happy to answer them!