External authentication (RADIUS, MySQL,Captive)

Good morning,
I need an explaination.
I bought a “RouterOS 3011 Mikrotik” a short time ago and now I have to configure the network as it follows:
-the user, to access the access point, is redirected to a login page where He can log in with username and password, sign in as a New user or log in with a social network account, everything controlled by a Radius server. The idea is to host the whole authentication process on its own server. Reading different forums, it seems possible; despite this, I haven’t discovered how to do it yet.
Do I have to redirect the user to the modified login.html or do I have to modify something else?
Thank you