I'm a new user of CiviCRM and I would like to ask for specific training courses for beginner users. Where could I find them? Thanks a lot!
There are a good set of answers on this post but since you are asking specifically about training, and that was about 'tutorials' these questions may be subtly different. Perhaps you could clarify in your question if you mean videos, online training, or direct/custom training
Three Important Thing to do
Join The Community - which you have done already
Attend a Meet up - look for the civicrm meetup/event/training near you
Sign up to Civicrm Newsletter
For more information please visit https://civicrm.org/
I guess this helps! - All the best for your learning
There is a great video by Oliver Gibson on YouTube titled "CiviCRM for Absolute Beginners". It's a part of the presentation he gave during CiviCon London 2015. If you are more of a YouTube self learner person I would suggest you to watch CiviCRM 101 Webninar(s). There is also a great webinar video by Erik Hommel and another one present on the CiviCRM Channel. Here are the links for webinar(s):
A number of CiviCRM Partner Organisations offer training: https://civicrm.org/partners-contributors
My suggestion: hire a consultant to analyse your org's needs and configure it with you, training at the same time.