I already have Hebrew yahrzeit dates and don't need conversion dates. How do I do that? Also, I don't know time of death for most of yahrzeit entries, how do I proceed?

Hi, thanks for using Hebcal.

If you know the Hebrew but not the Gregorian date, use the Hebrew Date Converter to get the Gregorian date and then come back to the Yahrzeit and Anniversary page.

In your case, if you already have the Hebrew date, you don't need the exact time of death. When you convert from Hebrew to Gregorian date, you'll want to use the "before sunset" option on the Yahrzeit page to retain the same Hebrew date.