That form is to be used to recover "accidental" VA withholding for reciprocal tax states.

NC does not have a reciprocal tax agreement with VA ...so you are taxed on all your VA-wages and must file a Non-resident VA tax return. Thus, VA is allowed to tax your VA wages....so you may not get any withholding back...depends on yoru total income situation.

NC also will include that VA income in it's tax calculations, since you are a NC resident, but to avoid double-taxation, NC will allow you to take a credit for the taxes that VA keeps (i.e. if VA refunds any of their withholding, NC only allows a credit for "up to" what VA kept)

In order for those calcuations to be done correctly..AFTER your Federal is fully filled out, then you work on the VA non-resident tax return, and you must do the NC Resident tax return last.  There are questions in the NC Q&A interview about taking that credit for taxes paid to VA...so look for it there.