How to express the year in heavenly stems and earthly branches, such as 20 15, and how to express it in the trunk and branch, and what is the corresponding number?

For example, plum blossom uses the trunk to represent 20 15, and the corresponding number is generally 20 18, each of which is correct. There is a regular tree planting every month every year, so sticking to my world means saying something with a trunk, that is, saying a corresponding number every day. This plum blossom is represented by the trunk in 20 15, for example. The corresponding number is generally 20 18, each with a symbol on the right. Every year, every month, there are corresponding trees to express, so sticking to my world to express words means saying a corresponding number every day.