Install a multi-track audio program. These are the core engines of any music software environment. Only multi-track software allows you to layer the many sounds necessary to create a music mix. There are many options, and some are free.
The program Reaper is a powerful application that competes with the best in the industry. The program is available for a licensing fee. However, the company has released the software for free download to allow anyone to try its many features. Unlike many demos, however, the program's creators have deliberately chosen to allow the program to function unrestricted, forever, with no expiration date. With Reaper, you can immediately start mixing audio tracks, and export the mix to a single audio file for mastering or CD duplication.
Acquire VSTi instruments. It used to be that synthesizers and sound sources required external hardware. The digital revolution has brought the same quality of sound generation into the software arena in the form of virtual instruments, or VSTi's. Many VSTi's are expensive, but just as many are available for free. Quality synthesizers to create any genre of music are available, from rhythm and beat generation to techno synths, guitars, and more. Any good multi-track program will integrate with many simultaneous VSTi's to create a virtual band with limitless music-making possibilities.
Master the audio mix in Audacity. This free open-source audio editing program contains all the tools necessary to perfect the final mix. After you export your song from a multi-track program such as Reaper, it will exist as a single audio file. However, the work is not yet complete.
Professional audio mixes must be compressed for maximum compatibility across all music playback devices, including stereos, car speakers, iPods, and more. You do not want your listeners frequently adjusting the volume dial due to constant variations in sound output. Audacity completes the process by lowering the loud volumes and strengthening the low volumes to create a better audio listening experience.