1. Open ssms2012
2. Right Click the Security Tab then new->login
3. When you click that a new window open like
this,
4. Give new instance name then choose which login method you have to use better
you create SQL Auth for Security and maintenance plans mainly this login is
helpful.
5. Then pick the default database as well as language then click Ok button.
6. After creating user check whether created or not in the security ->logins
tab.