Update of own WordPress Plugin

Hello,
I’ve written a WordPress-Plugin and I’d like to add the function, it can be updated by the user in the Admin-Panel. Also the user should get an advice, if a new version is online.
Now I have that value “Update Server” in the Plugin-paramters with an URL to my website.
My question is: What do I have to put on the “Update Server”, so that updating in the Admin-Panel becomes possible?

Couldn’t find anything with google…

Thank you!!

Johannes