です

de-su(pronounced des, not desu)

is, am, are

example : わたしはnameです

i am name 

は

pronounced WA when used as a particle, but the hiragana itself is pronounced HA

topic particle

example : わたしはnameです

the topic is "i", me, so it goes after the topic

を

pronounced WO or O

object particle

example : えんぴつをください

pencil please

the pencil is the topic/object of the sentence, so it goes after it