You'll probably have to connect to the computer running MyNode via ssh and install the pool software there. If you have no idea how to do that, feel free to ask any questions, or to use an LLM.
IMO using chatbot/AI/LLM should be last resort, especially when you can't understand/verify the suggestion. Besides, myNode also have documentation on
https://mynodebtc.github.io/ that include how to access terminal and connect via SSH.
I did read the doc guide but they dont have anything on how to add or create a solo mining pool. Their tech support sucks so bad that they barely reply. And mind you, I have premium support. When they finally replied, they said to use Datum, a public beta version to be used for solo mining. which I did installed and I point my miner to what I think its my node because it is using the myNode IP and port 23334. But, I can see that it is getting share like 1 every 5 mins or so, that slow. Very slow. Same miner when i point it to public pool, gets shares so fast