/etc/network/interfaces does not exist

So I am going through chapter 3 of LFS211 and it asks me to configure /etc/network/interfaces but this file does not exist, I only have
if-down.d if-post-down.d if-pre-up.d if-up.d

I'm running VMs of Ubuntu 20.04.4 server and desktop and neither of them seem to have it. Is there a work around so I can still do the lessons? Or am I missing something?

Thanks