congrats on doing your first taxes
the US Gov Interest question should only apply to the 1099-DIV.
If you held T-Bills at Fidelity you should see the interest from those on your 1099-INT Box 3 (some brokers report it differently on 1099-B but start with 1099-INT Box 3, hopefully Fidelity keeps it simple) and your brokerage statement should contain all the details if you need to review it.
for the 1099-DIV after you fill in the boxes you will get the checkbox/question about US Gov Interest and can provide a $ amount. For this you need to refer to the link below (all funds provide this sort of breakdown for official tax reporting, do not use prospectuses or other general research pages with asset allocations) and identity the fund(s) you held which paid dividends in Box 1a, and multiply the dividend paid by the fund (in the detail breakdown in the Fidelity consolidated 1099), by the percentage shown. See guidance in the link below also.
FXAIX has a very low % as it's all in equities. But look out for your cash position also, Fidelity usually defaults cash to SPAXX so you may have dividends reported on 1099-DIV from SPAXX which will have some US Government Interest. SPAXX symbol is not shown you have to look up by name for that one (Government Money Market Fund). If you have multiple funds with US Gov amounts you have to add it up offline and put the total into TT.
This amount doesn't affect your Fed return but should feed through to your state return along with 1099-INT Box 3 as a subtraction/exemption from your state tax so check that when you do your state.
https://www.fidelity.com/bin-public/060_www_fidelity_com/documents/taxes/TY24GSESupplementalLetter.p...
