With my few years of teaching experience I have understood the steps of learning musical instruments for a bigginer should be as bellow:-
1. Basic understanding of make of the instrument that one is going to learn
2. Learning initial pieces and exercises written in standard staff notation
3. Learning theory of music along with practical lessons
4. After compliting foundation of learning one must try to teach him/herself the pieces that inspires him to play the instrument and try to play it along with backing track if available.
Do the right practice, do a lot of practice thats it.