Sometimes we are bad about crossposting things to the forums, as the Kansas Discord is way more active than the forums here, and announcements are generally made there first. There is a Google form for IBGAs that is posted after each game, the one for this months BGAs was here: https://forms.gle/BnsiPAcroo2EtPSv5 however the deadline for this game was on 2/29/2020, so it's now past. I believe that deadlines are generally ~2 weeks before the next game.
As far as the response, that really depends on what the BGA involves, but I believe the format is usually returned via the email you provide in the form.