Generalized music tutorials for beginners cover several different areas. A music tutorial for a specific instrument would be quite different from an overview for all instruments. But there are many features that all instruments share.
While the means each instrument employs to make sound may be quite different (blowing, striking, bowing, etc.) the sounds for all musical instruments in Western music are notated and written down in some fashion.
The modern system of musical notation that utilizes five horizontal lines with small circles indicating notes was first developed by a dyslectic German nun named Hildegarde von Bingen, an altogether remarkable figure from the 1100's.
This five-lined system, used to communicate musical content, has several advantages and disadvantages.
The biggest disadvantage with the von Bingen five lined system is that almost every person who is not a trained musician finds the system very difficult to learn.
The biggest advantage is that, once learned, the system allows a composer to show the entire musical texture at one glance, assuming the user/musician can decipher the intricacies.
Once you've mastered reading music, a task that many never master and takes decades, you're ready to play the notes you have read on the page on a musical instrument.
Every instrument is radically different in physical requirements and dexterity.
The piano is generally accepted as the easiest choice and quickest way to start playing music.
The reason for this is that, almost alone among instruments, the piano requires your two hands to perform more or less the same task. Think of the violin, or wind instruments, and you'll see people contorting their bodies into uncomfortable shapes to produce the sound.
In this sense, the piano was the first computer, (perhaps with the abacus) complete with "keyboard."
The most generalized tutorial consist of two pieces of information: you will have to read WHAT to play, and then you will have to actually PLAY it on some instrument.
Both of the above are far harder in actual practice, and either one can occupy a lifetime.
The most logical course is to learn to physically play before you immerse yourself in reading music.
The reason for this is that anyone can play music far harder than they can read.