I have built up a private chain between by computers. And now I want to make one of these computers as a mining pool in this private chain. could you please tell me how to achieve this function?
You have to use a mining software pool like Open Source Ethereum Minig Pool
I've used this in the past to set up private pools to mine ethereum and forks. https://github.com/dataspark-co/eth-pool-docker-infra
It's the Open Ethereum Pool, but containerized with docker.