This article could be very short. "Get instrument. Practice regularly."
Much like the advice for losing weight will always be the boring 'diet and exercise', and the advice for succeeding at a job is 'don't call your boss a stupid jerkface', learning an instrument takes the hard work of consistent practice. The internet, as ever, is here to help.
If you want to start simple, start with an instrument that anyone can play, provided that you have functioning lips and vocal chords: the kazoo. If you still need help, you can get 'the seminal work' on the subject - 'The Complete How To Kazoo' - through used copies on Amazon:
But perhaps you'd like to play an instrument that doesn't sound like a possessed door buzzer. That's fine, but how do you stay motivated to practice? Although this NPR article is about getting children to practice, it's good advice for all:
YouTube has countless music lessons. Here's some advice about guitar channels:
This enthusiastic fellow has hours and hours of free piano lessons:
You're not sure you want to play guitar, piano, OR kazoo? What DO you want to play? This article helps you consider:
Spend some money on a professional teacher; getting the form correct from the start is invaluable. Try:
Learning to play an instrument is worth all the hard work. Then again, as this band shows, all you really need are four chords.