Bay Tree Propagation

Would you know how to propagate a bay leaf tree? I would appreciate it if you let me know.

The best way is by stratified fresh seeds. Richters sells these and ships them to the purchasers as soon as they start to sprout - usually in April or May.
It is possible to root cuttings of bays, but they do not root easily. A rooting hormone and a mist tent with bottom heat would be needed for good results. The book "Growing Herbs from Seed, Cutting & Root" by Thomas DeBaggio (catalogue # B4280) might be a good addition to your library, since it discusses all these methods in great detail.