Anyone can hybridise two different magnolia varieties when they are in flower to create a new hybrid (or rather lots of new hybrids) of your own.
Cut and take a flower from one magnolia plant, the ‘Pollen Parent’ and spread the pollen exuding from its stamens onto the stigma (or female reproductive part) of the ‘Seed Parent’ flower on the other magnolia plant.
Then remove all the tepals (petals to you and me!) from the ‘Seed Parent’ flower as well as the male pollen bearing stamens. This should ensure that the ‘Seed Parent’ will not get visited by other winged insects carrying other different pollen as, without the petals, there is nothing to attract them. It will also avoid self fertilisation whereby the flower fertilises itself with its own pollen.
You then clearly mark the twig on which your cross has taken place and hope that the stigma will grow and develop into a seed pod with viable seeds which represent your unique cross. If it does, and there is no guarantee at all that it will, then the seed can be collected in October or November when the seed pod splits and the bright orange individual seeds can easily be seen.
When you look in October or November you might be lucky enough to find a seed pod. Click for Further reading on collecting, storing and propagating seeds.