title - necessary (alt titles are optional but nice to have if you can provide them)
author - not necessary at the page creation, but can't you google it or get it from the raw? someone wil likely add it for you eventually but I assume it's one of your projects so you have it easiest to get that info I think
cover - not necessary; if not present ppl seem to opt for using the first page as a cover instead (and I'll use it as an opportunity to remind everyone reading this that there's no auto-resizing of cover images so please scale them down to something like 400 px tall before adding them)
year of publication - that's for baka updates; don't add it here
genres - not necessary
description - someone will write one eventually
generally if you have a chapter to release, feel free to make a barebone page for it to fill it later when you have time or more info