For creating New SQL Instance follow below steps.
Connect the MS SQL server and right click on Database for creating fresh instance.
Then, Select New Database
Give the Database Name and Click Ok.
Now, Create a Database login user.
Open Security tab and right click on Logins.
Select New Login
Give the Login Name and Select SQL Server authentication
Uncheck the “Enforce password policy” and at end select the default database then click OK.
Open the same login database properties and Select the User mapping. Select the same database that need to map .
And select the Database role its should be “db_owner”. So the current login user have all permissions.
Click Ok.
Once you click on Ok , Database instance permission will configured. Now you can login with that details and Check Database connection.