Roth IRA contributions directly done on w2 form from emplyer. Do I report this on taxes

No, if you make Roth 401k contributions reported on your W2, you do not have to report on your tax return.  

Almost never, but we have to be extremely careful about definitions.

A qualified workplace plan (401k, 403b, something else) is NOT an IRA.  An IRA is a private arrangement between you and a bank.  Qualified plans are sponsored by your employer and held at a bank or broker in trust for the employees.   Qualified workplace plans are only reported on your W-2 using special codes in box 12 and they are NOT separately reported by you.

However, there is another type of retirement plan called a "payroll deduction IRA."  With this plan (intended for small businesses), you have an IRA at a bank or broker, and your employer makes contributions for you automatically from payroll.  This type of plan is an IRA, is not a qualified workplace plan, and is NOT reported on your W-2.  If you and your employer participate in a payroll deduction IRA, then you do report the contributions as if you made them yourself. 

Enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form, nowhere else in TurboTax.