Exactly. You can also hear some real recorded pronunciations on sites like Forvo and Dict.cc. Bookmark them, as these sites will be very helpful when you think the robo-voice on Duolingo is getting it wrong (which it does sometimes).
When that happens, please don't just write endless comments about it - click the "Report a Problem" button so that Duolingo can be improved! Improvements are only made by those problem reports - the programmers do not read the comments!
It really helps to learn the alphabet and it's pronunciation in what ever language you are learning. There is one at http://german.about.com/od/pronunciation/a/The-German-Alphabet.htm or http://www.bbc.co.uk/languages/german/guide/alphabet.shtml. Both have audio with pronunciation and tips. The BBC one has also other languages on their site. It really helps so one does not try to ponounce the German, or any language one is learning with english/american/any native language sounds. No matter how well one learns the vocabulary, people will have a hard time anderstanding if the words/letters are just strung together english sounds. I found out the hard way.:)
You can use it pretty similarly to English " ich bin Julia /klein/alt/jung... = I am Julia /little/old/young...." "Ich bin" is a conjugation of "sein =to be".
"Ich heiße = I am called" is a conjugation of "heißen" you can use when you want to say I, he, she, they... is/are called. It can't be used in other instances like "sein -to be"
For example, if you say: "sie sind neu " it means "they are new" but if you used "sie heißen New" you would be saying "they are called New" which would only make sense and work if that was actually their name.
It really helps to read the "tips and notes" on Duo. there is a conjugation table for "sein" at: https://www.duolingo.com/skill/de/Plurals :)
I also really like using http://www.dict.cc/?s=hei%C3%9Fen to clarify/translate. The site has audio and often entire phrases as well.
"Justin"... or "Dschastin, Schastin, Tschastin", which represent how some people pronounce this name, which was borrowed from English but doesn't really fit into German phonology.
(It's a stereotypical lower-class name, along with Kevin, Chantal, and a number of others. See https://en.wikipedia.org/wiki/Kevinism .)