Non-clustered indexes have a structure separate from the data rows. A non-clustered index contains the non-clustered index key values and each key value entry has a pointer to the data row that contains the key value. There can be maximum 999 non-clustered index on SQL Server 2008/ 2012.
Link for reference: https://msdn.microsoft.com/en-us/library/ms143432.aspx
CREATE TABLE Employees
(
ID CHAR(900),
FirstName NVARCHAR(3000),
LastName NVARCHAR(3000),
StartYear CHAR(900)
)
GO
CREATE NONCLUSTERED INDEX IX_NonClustered
ON Employees(StartYear)
GO