- Listen to songs. Listening is a musician's most important skill. Learn to listen carefully to all different dimensions of music. Listen to a wide variety of music, and especially listen to music that you love. Listen with your whole being, not just your ears. Listen to recorded music, get out to live concerts, and watch music videos and recorded concerts as well. Go dancing so you can listen to music via your arms, legs, and hips.
- Play songs. Learn to play keyboard or guitar or another chord instrument, and play and sing through songs that you like.
- Learn to read music. You should learn to to read and play at least a melody line, and also chords written in standard chord notation.
- Learn to write music. If you can play a melody line, you should be able to write it down on music paper.
- Perform. Even if you only do it informally for friends and family members, you'll need to have the experience of playing a song for an audience.
I'll post some links here as I find helpful basic music instruction online. And of course, you'll find books in every library on the basics of music.
Because music is so multidimensional and tangled up in itself, there is almost no way to start learning it from scratch without a teacher. It's almost like trying to solve a crossword puzzle in a foreign language. That's why my first recommendation for a beginner is to pick an instrument and find a teacher.