If I have universal music in my head, how do I record it to a medium ?

I'm talking about the first steps of music composition.

If I have music in my head , how do I make it into a reality without singers readily available ?

I am aware of computer softwares . But do you think I have to go to school and learn music and also , how do I set up a music studio ?

Like I said earlier, go to a local recording studio.And search the web about info on it