https://en.wikipedia.org/wiki/Dramatis_personae

This is one way to look at it. It's very much a short description of who is who in your work. Here's a short except from my WIP of Dramatis Personae:

Lorelei - human, Captain, trained Navigator, main character- trying to get through life without becoming indentured or a slave (Dark hair, approx 5’5”, hazel eyes, white but not pale or marshmallow, almost petite, 24-28)

Peregrine - human, pilot, prankster?
(graying deep brown/black wavy hair, dark brown eyes, olive skin, approx 5’11”, medium build, 48-53)

Uehe - “Dead” cunzan, engineer
Uehe, a furry creature called a cunzan who stood shorter than her shoulder with whiskers and a short tail, poked his nose out of his nest. (Coloring: gray to black, claws on fingers and toes, black eyes that nearly don’t show the white, almost 4’ height, oversized “rat”)

Mine goes on like this, a name, a job, species, size, description, and anything else i might need. Sometimes there are gaps (I haven't found those details yet but when I do I throw them in).

Yours may be longer or shorter, depending on the important notes. Maybe all your speaking characters are human so you don't need to label the species unless there's an important pet cat or dog or something like that. Also, it keeps the details close. If I know Lorelei has dark hair, she can't suddenly turn blonde without a reason in the narrative. Uehe has a very specific definition of "Dead" and it had nothing to do with actually dying. But that is also listed within my settings definitions.

Remember some characters may only have names to start. That's normal. You may have other details and the name comes later. That's also very common. But as you write the novel, use that dramatis personae and settings definition list to keep these things straight. They're working documents so when you randomly add a scene that wasn't in your outline and use a character who broke a rule- you know it from these documents and you can fix it (maybe at that time, maybe later).

I did one NaNoNovel before the Prep started, which also brought me to be excited for the Prep creation and to do everything I could to help Brandiwyn🎶 make it amazing (and that's been 15 years now!). That book taught me I needed more of a structure before writing so much, and also that it can all be fixed later but it is harder without the pre-working. Over time, I've used the Prep assignments for projects outside of NaNo, still learning and making everything better even if I don't do the whole thing for every single project.

Happy hunting for your characters, large and small, through this Prep and through Nano and edits to come.