What the best method to use the right or true fingers for any Guitar Arrangements?have you any tips?
Your question is not very clear. What do you mean by "right"? What are "true"? And, lastly why are you referring to arrangements? Previous answers offer some advice on left hand fingering and right hand plucking techniques but are you asking how to determine authentic arrangements of the "fingerings" or voicing of the song? If so this needs to be answered on a case by case basis.
I would point out that there are competing schools of thought of the "correct" way to use both the left and right hands. And I am of the opinion that "schools of thought" can become cult like. I'd advise you to use common sense principles if you are NOT a beginner. If you are a total beginner you need a simple book to teach basics. Free stroke and support stroke for right hand are both valid and with practice the free can produce good tone and volume. As for left hand "on the finger tips" vs. slightly flattened. I'd say that the common sense approach is that you do not want to accidentally dampen string that would resonate with the notes being played if at all possible. This leads to "on the tip" approach. But in reality you will need to adjust with the situation.
Also, with the right hand use of index, middle, and ring should start as soon as possible.
Other good books to add to Mel Bay series are Carcassi and Pepe Romero, also for beginners Parkening's book.
The whole idea is to make it as easy as possible. So with the left hand (fretting), as much as possible, you're going to use one finger for each fret - first finger on first fret, second finger on second fret, etc. for all four fingers, in whatever key you're playing in.
As for the right hand, there are several options. I would get an intro book on classical guitar to see - Mel Bay makes a decent one. In Flamenco (which I play) we often use a rest stroke, where your thumb stays on the 6th string, your first two fingers alternate playing notes, and they stay on the strings after they play. (This is easier to see than explain - I would look at these videos on You tube - "Flamenco rest stroke" or just "guitar rest stroke".). Mel Bay also has a Flamenco book if you want to learn more.
Hope this helps!