If I choose to participate, how will I be informed about where and how my works are used under the license?

In your future royalty statements from STIM, you will be able to see where the income originates, whether it relates to the training of an AI service, or generated music (output) from a licensed AI service where your work has had an influence. The payments will be reported in a similar way to how you currently see income from streaming, radio, TV, etc.