FreePBX & Digium D70 phone side buttons

I have read and read on this.

What I understand is that Smart BLF is supposed to be able to pull an address book and fill in the side car button info. @mdavenport referred to in 2020 to a document I can no longer find, but the quoted part indicates I need to make sure to set the blf_contact_group in res_digium_phone.conf.

But when I went to lookup how, I saw that in 2021 @lgaetz pointed out that I’m not supposed edit that file directly at all.

So… I’m left wondering how I’m supposed to do this…

If anybody can shed any light, I’d be grateful.