Well, in English it may look the same, but you have to pratice thinking in japanese to understand better.
前 is a word that indicates direction or movement in space or time, so it needs a particle to indicate where exactly the object that it refers it is.
And you should use います instead of です, because the main subject of it's 私.
That's why the correct form is:
Try to think of です as the To Be form in English. Thiking this way, you can't say "I'm the front of the guy." you have to put "in" in the sentence to make sense, right?
It's the same when you need to say where the book is.
So, saying 本は机の上にあります。you will be saying "The book is on the table."
As for 本はどこですか。and 本はどこにありますか。
In the first sentence you are asking simply "Where is the book?" but in the second you're asking where exactly is the book, you're asking for directions to where to find it.
Hope it help. I'm not at a high level, but I did my best to explain.