Registering Rendered Control

Question

I need help. I've created a rendered control and I can't get it to register on my aspx page. I'm trying to do it without putting it on the tool box and dragging it over. I've tried many things such as..... <%@ Register TagPrefix="yellow" Namespace="YellowCustomControl" Assembly="YellowControl %>, and many different combinations (changed the names). Anyways It's not registering right, and I'm not sure if I'm missing something, or just not doing it right, so help would be nice!!! :) Thank you