Need some help for my server

so i have my server online now

now i have 2 problems
My world is empty but thats because i have used the standard mangos.sql

anyway

i know that you need the same version etc. etc. but i have no clue how to replace it ? so i can install a new mangos + database ( and were to download them )

Second question

how do i let people create a account for my server?

if you got time to awnser would be great =)