Where do I enter in TurboTax a Traditional IRA that I converted to a Roth IRA? I rec'd Form 5498 with $'s in Box 3 (Roth IRA Conversion amount) & Box 6 (FMV of account)

You should have also received a 1099R from the Traditional IRA.  If you didn't get it ask them for it.

The easiest way to get to the 1099-R entry screen is to simply search for 1099-R (upper- or lower-case, with or without the dash) in your TurboTax program and then click the "Jump to" link in the search results.

Enter a 1099R under

Federal Taxes Tab or Personal (Home & Business)

Wages & Income at the top

Then scroll way down to Retirement Plans and Social Security,

Then IRA, 401(k), Pension Plans (1099R) - click Start or Revisit

There are 4 boxes.  Be sure to pick the right box for the kind of 1099R you got.

If you are filing a Joint return be sure to pick which person it is for.

You don't enter Form 5498 in your tax return. You don't actually enter anything about the Roth conversion. You just enter the distribution from the traditional IRA. As VolvoGirl said, you should have gotten a 1099-R for the distribution. The 1099-R is what you enter in your tax return.

During the entry of the Form 1099-R for the distribution from the traditional IRA you do need to tell TurboTax the amount of that distribution that was converted to Roth, otherwise TurboTax won't track your Roth conversion basis properly and you could end up with an inappropriate early-distribution penalty being reported.