Need Help Writing Search Query

I am not very familiar with the syntax of MS SQL and I am trying to write a stored procedure which would do a search and return matching records.
This is what I need to achieve:
for instance I create a form with 4 text fields
- First Name
- Last Name
- Employee ID
- Date

I am interested in writing a stored procedure that would run a select query based on the input in the text fields
e.g.
- if the user enters First Name and the Last Name (leaving Employee ID and Date fields blank) query should be something like
select * from Employee where FirstName like @FirstName and LastName like @LastName
- or if the user enters only the Employee ID stored procedure should run a query similar to
select * from Employee where EmployeeID like @EmployeeID