I am not 100% sure that I get the difference between あります and です.
I understand parts of it, for example "わたしはマルクスです" using あります doesn't make sense for me here as I think it is more of a "there is" word.
But in this sentence I am not sure about the difference, or how it would translate
ほんは つくえの うえに あります
vs
ほんは つくえの うえに です
Does it translate differently and if it does, how?