The biggest problem beginner adults have when it comes to learning music is not being clear about their goals.
If you don't know where you want to get, how will you how to get there? So, first of all you need to decide what you want to learn to do.
To sing? To play an instrument? If you want to learn to play an instrument, what exactly would you like to be able to play? Or do you want to be able to improvise and express yourself with music? After you decide what you want to do, you need to choose how you'll get there.
The only effective way to learn music is to follow a course created for beginner adults (following a curriculum designed for professional musicians may take you years) or attend classes at a music school.
You will never get anywhere on your own, because to play an instrument well, to improvise or play by ear you need a system.
You need a combination of certain knowledge and certain skills.
Sure, you may acquire skills and knowledge by studying on your own.
Obviously, there's a ton of stuff available for free on the internet.
Some of it is actually pretty cool.
However, what you'll get this way will not be a system.
You will not see the whole picture by getting a piece here and a piece there.
Not seeing the whole picture you will be very limited in what you'll be able to do.
That is why you need a good music teacher or a good home-study course that will guide you to your goal step-by-step.