How do I attach, piece & block on my dresden plate quilt?

I have my circles ready to attach to the 15" block. They are rounded on the ends. And already sewn in a circle. I do not know how I need to attach them to the block. They are pre-cut with a cicular edge so they are rough edged right now. I do not have my center circles attached yet. I thought I would turn them under and blind stitch them onto the block as the last step of block embly. I thought about z close zig zag stitch around the edges with my machine, but I just don't know what to do. Please give me easy instructions. This is my first quilt