Reaching out to a creator for help - Unable to edit colors on an AE Transition pack

Demo video says it has changable colors.
Found the Color Control layer- and change my colors- but nothing changes on the boxes and shapes represented. I even change it on the individual item level, and still no changes.

How can I reach out to the author for support?

Only the author can help you. Write him. But remember that he is not obliged to help you, since you did not buy the project on the Envato market, but downloaded it by subscription to Envato Elements.