Hello, Daniele Pugliesi! Welcome to Wikivoyage.
To help get you started contributing, we've created a tips for new contributors page, full of helpful links about policies and guidelines and style, as well as some important information on copyleft and basic stuff like how to edit a page. If you need help, check out Help, or post a message in the travellers' pub. If you are familiar with Wikipedia, take a look over some of the differences here.
Your contribution of a pagebanner to Alcamo is very much appreciated, but because of this site's policy forbidding the use of montages, it had to be reverted. I hope that's not too disappointing, and that you stick around.
All the best,