What is the most efficient way and tools to learn and understand ranges for a beginner ?
I've found that personally the best way to learn hand ranges is to have flash cards, or the ability to check each chart in each spot with ease.
Fortunately training sites like Raise Your Edge, Poker Coaching, Upswing (and I'd have to imagine Run it Once) all have "range viewers" which allow you to do this.
Lately I've really committed to improving my ranges and of them all I found the pokercoaching premium preflop charts tool to be the very best.
You can get a half price 1st month here:
http://pokercoachingoffer.com (it also includes a bunch of tournament training programs as a bonus)
Take a month, work with those charts, study them, learn them, try to memorize and test yourself, and I think you'll find in a month you've learned a ton.
And if after that 30 days you got what you wanted, just cancel the membership
It's about 5% of what it would cost to get access to similar charts on other sites (since most of them require you to invest in a $1k training program to get access to the ranges)
Hope that helps!