With high range of music composing facilities, Myna has been the center of all music composing freebies.
First step is obviously going to http://www.aviary.com/tools/audio-editor
and then click on Launch
A Screen Like this would appear
I would However advise you to register your name on the site first and then proceed, as it would help you in saving the file, avoiding any accidental loss
Here is a video depicting Myna and its components
Now you may import the music files from your computer or from the predefined libraries already stored in aviary’s servers. However using that, you are bound by aviary. I would preffer downloading music from predefined galleries in freesound.com or any other site, store it in your computer and then upload it to aviary to compose it right.
Predefined roc libraries in Aviary audio myna
Imported library by the user from third party sites
Using these files is hugely easy, just drag and drop it to your workplace and place it according to your needs. Other info is given properly in the cmkt videos.
Steps for - How to import music files ?