How to set Login and Password for SQL Server Authentication mode?

While you configure MS SQL, it will get configured under windows authentication.  You have to change this mode and set password.  

Login using windows authetication and open a query browser.  Type the following:

ALTER LOGIN sa ENABLE

GO

ALTER LOGIN sa WITH PASSWORD='password'

GO

First of all you enabling SQL Authentication mode and then set password for sa.  sa is the default login.