Hi riesta,
There is any specific reason for making you change the authentication logic?
You should not create another one since OutSystems uses a lot of business logic based on Users module, like permissions on screen and etc.
If you want to create some custom functionality you can always clone the Users Module or try to extend it.
But you shouldn't create it from zero.
To clone Users module just open it from any other Module that uses it, and it will prompt you saying that you can't open it unless you clone it.
After opening, publish it and you will have a new User Provider Module in your environment.
Once this is done you can use this new Module as an User Provider of others modules, you just have to configure it in Module properties.
Like this:

Hope it helps!
Cheers and Regards,
RR :)