First, in Which country are you trying to sale your book?? because you're from italy, but your project is in English... so... it's confuse
If you are going to work in English, I can help you. I Speak Native Spanish, quite well English and some Italian
Currently I work as Business Intelligence Specialist, for a Swiss Comapany that Sales Led Light Technology in Amazon USA.
I have 3 year working with amazon for many brand. Brands from USA, Spain, Argentina, México, Germany and U.K.
I use tool for Keywords Like: Jungle Scout, Helium 10, Sonar.
Let me know if I can help you
Buona fortuna con il tuo libro. Best Regards. Nicola