Quoting Steve Litt (slitt@???):

> You know what would really be fun? An installer that asks *all* of the
> necessary questions right at the front, so you can walk away and do
> something else while it installs itself.

https://wiki.debian.org/DebianInstaller/Preseed

As the page says, start with a known good, default preseed file, such as
the one linked to.