With all due respect, you have asked a number of questions with respect to a foreign inheritance and have been advised to seek professional guidance.
The instructions for filing Form 3520 (regarding who must file and when to file) are at the link below.
See https://www.irs.gov/instructions/i3520#idm139632651217968
Note that TurboTax does not support Form 3520; you should seek a consultation, in person, with a tax professional and/or a trusts/estates attorney for this matter.
