by VanessaE » Tue May 07, 2013 23:56
Each server, being owned and run generally by different people across the Minetest community, has a different registration method, though usually you just have to make up an in-game name and password, and use those each time you sign into that server.
Some servers go a bit further - for example, on mine you have to make a forum account first (which you already did). On redcrab's server, there's a semi-automated sign-up via email.
Also, please be more specific, "it didn't work" is not enough information.