I think the Instructions for the 4684 are confusing, and certainly not clear.  It doesn't specifically state how to claim a non-qualified federal disaster (such as the third most expensive Hurricane ever - Ian).  I figure that means that the loss is reported on Sch A along with any other itemized deductions.  If you don't itemize and just take the Standard Deduction, it appears that your loss becomes moot.  Annoying to many of the victims.