I have heard that kabala is some jewis book of black magic, is it true?
It is not true. Magic is forbidden in Judaism. There are some cheap books that describe some stupid rituals and call it "Kabala" but they are all frauds.
Kabala describes spiritual world, just like physics describes physical world. But unlike the natural sciences, Kabala concepts are very allegorical, it is impossible to understand them literally. Also, it is very complex, it is impossible to understand it without many years of preliminary study. I don't understand it at all.