How to write a library for nft?

Question

linux

We were given a task with a friend, to write our own library for nftables, which would implement such a thing: "We ping a previously known non-existent IP, and he answers that everything is ok."
Unfortunately, they are very superficially familiar with Linux, which is why it is not clear how to write a library at all? How to connect it? And where do you start?