I have a Dawn Redwood in my backyard that dropped hundreds of cones last year. I collected them and placed them in a shoe box that I kept in a dry outdoor unheated shed to winterize. In the spring I shook the box and hundreds of seeds spilled out. I soaked about the seeds in plain water and planted them in a tray of loose, loamy, sandy soil covered with a fine layer of sphagnum moss to cover the seeds. I placed a clear storage container over the tray to create a mini greenhouse. I have had about 30% germination. If you only have one cone (about 10 seeds) you will probably only get 2 or 3 seeds to germinate. You can buy seeds online pretty cheap. The most important thing to do is winterize the seeds in a dry environment.