Unity to steam steamworks achivements

I dont have a game on steam, so I have no idea what Im talking about.

But, from a simple google search I got this site: https://partner.steamgames.com/documentation/api You should be able to log in and click the first link and find the API documentation on achievements and stats.

If you don't understand the API documentation... I guess you could contact Valve, send a mail, call them. Or contact a Valve employee, you can find most of them on linkedIN, and ask them personally. Or seek out someone who has done it before, like some indie-devs or even large companies, and ask them. But the easiest I think would just be to look over the API again and try to understand!

Good luck