You should consider completing this path on the Academy https://gettingstarted.mendixcloud.com/link/path/56
It takes you through creating your own login screen and I think it will solve a lot of your questions :)
There are multiple ways to achieve this. It might be worthwhile to consider to take a look at the forgot password module as this module comes with sign up logic.
These are the errors I am facing, after downloading forgot password and its dependent modules.
Could anyone share your suggestion to resolve these errors.