訂正<ていせい>correction これわ→これは 回答<かいとう>answer ある 1. location＋に＋subjectが＋ある(verb, used to describe existence of an inanimate object) 机<つくえ>の上<うえ>に本が有<あ>る。There is a book on the desk. ※あるis written by hiragana or kanji. 2. subjectは／が＋で(助動詞<じょどうし>auxiliary verb of assertion)＋ある（補助動詞<ほじょどうし>verb which used like a auxiliary verb to describe a judgment） 机の上に有るのは本である／本だ(dearu→dea→da)／本です(polite form)。The thing/object which is on the desk is a book.　※あるis written by hiragana only. いる 1. location＋に＋subjectが＋いる(verb, used to describe existence of an animate object) ベンチの上に猫<ねこ>が居<い>る。There is a cat on the bench. ※いるis written by hiragana or kanji. 2. subjectは／が＋verb＋て(particle to connect)＋いる(補助動詞verb which used like a auxiliary verb to describe a continued state) ベンチの上で猫が寝<ね>ている。A cat is sleeping on the bench. ※いるis written by hiragana only.

です - no translation. it indicates the courtesy / formal sentence. it placed after the nouns, adjectives, adverbs, etc. but not after the verb. ある - verb "have". Btw, it indicates an informal appeal. formal あります. I have book - 私は本がある(watashi wa hon ga aru). This is book - これは本です(kore wa hon desu). P.S. sorry, my English is poor.

as far as I know desu is used with a noun hon desu, it's a book aru is the same with a particle in between hon ga aru there is a book iru is used with animated thing neko/inu ga iru there is a cat/ dog