Submitting your beats for Content ID is really simple. For existing beats, head to Dashboard > Monetization > YouTube Content ID and click +Submit Beats on the left
Select your beats, agree to the terms & conditions, then hit submit.
For new uploads, assuming you have already been accepted into the Content ID program, you can submit these beats by simply clicking the Submit To YouTube Content ID checkbox on the upload page, and the beat(s) will be submitted automatically once upload is complete.
Click here for information on how long it will be before your beats begin earning revenue.
Content ID is available to Platinum members only. If you have a free account, you can upgrade here.